* p2p/pex: Allow configured seed nodes to be offline

Previously you couldn't startup tendermint if a seed node was offline.
This now allows you to startup tendermint, as long as all seed node addresses
are formatted correctly. In the event that all seed nodes are down,
and the address book is empty, then it crashes with an informative error msg.
(This case doesn't occur if no seeds were specified)

Closes #1716

* (Squash this) Address melekes' comments

* (squash this) fix package imports

* (squash this) fix pex_reactor comment

* (squash this) add a test case

also, remove excessive log message

Refs #2072

This is to reduce wait times when initially connecting. This still runs checks
such as whether you still want additional peers.

A test case has been created, which fails if this change is not included.

* Removed unnecessary onStart & onStop calls in reactor

* Refactor OnStart & OnStop in reactor

* Removed redundant OnStart func in reactor

Refs #1706

Currently the top level directory contains basically all of the code
for the crypto package. This PR moves the crypto code into submodules
in a similar manner to what `golang/x/crypto` does. This improves code
organization.

Ref discussion: https://github.com/tendermint/tendermint/pull/1966

Closes #1956

Refs #1720

* Add private peer ID tracking to AddrBook

* Remove private peer tracking/blocking from pex

* debug level msg when we fail to add private address

This commit switches all usage of math/rand to cmn's rand. The only
exceptions are within the random file itself, the tools package, and the
crypto package. In tools you don't want it to lock between the go-routines.
The crypto package doesn't use it so the crypto package have no other
dependencies within tendermint/tendermint for easier portability.

Crypto/rand usage is unadjusted.

Closes #1343

This reverts commit d02c5d1e30.

Refs #646

Refs #646

* new config option for external address to advertise
* if blank, defaults to best guess from listener
* if laddr ip address is also blank, default to IPv4

Fixes #1830

remember that PeerSet#Get can return nil

* config: rename skip_upnp to upnp

Change default option to enable upnp.

Closes #1806

* doc updates

- fix comment and set UPNP to false in TestP2PConfig
- add UPNP to config template
- update changelog

This reverts commit 96a3502

As both configs are concerned with the p2p packaage and PeerConfig is
only used inside of the package there is no good reason to keep the
couple of fields separate, therefore it is collapsed into the more
general P2PConifg. This is a stepping stone towards a setup where the
components inside of p2p do not have any knowledge about the config.

follow-up to #1325

In some scenarios like tests we want to disable the guard which prevents
peers connecting from the same ip.

Fixes #1632
Closes #1634

* fix before/after in isBad()
* allow multiple IPs per ID even if ID isOld

* replace math/rand with tmlibs equivalent.

* update tmlibs dependency

* Replaced NodeInfo PubKey to NodeID

* Fixed tests and replaced NodeID with ID

* Removed unnecessary method ID()

* Fixed codec_test.go

* Fixed codec_test.go

* Removed unnecessary bracket

* Fixed all tests

* Fixed peer_set_test.go

* Fixed peer_test.go

* Fixed common_test.go

* Fixed common_test.go

* Renamed node_id to id

* Removed peer.ID() from RPC net.go

* Replaced NodeInfo pubKey to ID

* Fixed codec_test.go

* Fixed peer_set_test.go

* Fix pex_reactor_test.go

* Refactored code for privateKey initiali

* Fixed peer_set_test.go

* Fixed test.proto and removed orphan string in codec_test.go

* Fixed pointer to a string

* generate node_key when running tendermint init

* [docs] prefix IPs with node IDs

Refs #1429

* gen_node_key cmd

* [docs/specification/secure-p2p] add a note about config

* fix data race

Closes #1442

```
WARNING: DATA RACE
Write at 0x00c4209de7c8 by goroutine 23:
  github.com/tendermint/tendermint/types.(*Block).fillHeader()
      /home/vagrant/go/src/github.com/tendermint/tendermint/types/block.go:88 +0x157
  github.com/tendermint/tendermint/types.(*Block).Hash()
      /home/vagrant/go/src/github.com/tendermint/tendermint/types/block.go:104 +0x121
  github.com/tendermint/tendermint/types.(*Block).HashesTo()
      /home/vagrant/go/src/github.com/tendermint/tendermint/types/block.go:135 +0x4f
  github.com/tendermint/tendermint/consensus.(*ConsensusState).enterPrecommit()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:1037 +0x182d
  github.com/tendermint/tendermint/consensus.(*ConsensusState).addVote()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:1425 +0x1a6c
  github.com/tendermint/tendermint/consensus.(*ConsensusState).tryAddVote()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:1318 +0x77
  github.com/tendermint/tendermint/consensus.(*ConsensusState).handleMsg()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:581 +0x7a9
  github.com/tendermint/tendermint/consensus.(*ConsensusState).receiveRoutine()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:539 +0x6c3

Previous read at 0x00c4209de7c8 by goroutine 47:
  github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.(*HexBytes).MarshalJSON()
      <autogenerated>:1 +0x52
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.invokeMarshalJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:433 +0x88
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec)._encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:82 +0x8d2
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:50 +0x10e
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSONStruct()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:348 +0x539
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec)._encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:119 +0x83f
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:50 +0x10e
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSONStruct()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:348 +0x539
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec)._encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:119 +0x83f
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:50 +0x10e
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSONStruct()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:348 +0x539
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec)._encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:119 +0x83f
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:50 +0x10e
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSONStruct()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:348 +0x539
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec)._encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:119 +0x83f
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).encodeReflectJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/json-encode.go:50 +0x10e
  github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino.(*Codec).MarshalJSON()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-amino/amino.go:296 +0x182
  github.com/tendermint/tendermint/rpc/lib/types.NewRPCSuccessResponse()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/lib/types/types.go:100 +0x12c
  github.com/tendermint/tendermint/rpc/lib/server.makeJSONRPCHandler.func1()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/lib/server/handlers.go:152 +0xab7
  net/http.HandlerFunc.ServeHTTP()
      /usr/lib/go-1.9/src/net/http/server.go:1918 +0x51
  net/http.(*ServeMux).ServeHTTP()
      /usr/lib/go-1.9/src/net/http/server.go:2254 +0xa2
  github.com/tendermint/tendermint/rpc/lib/server.RecoverAndLogHandler.func1()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/lib/server/http_server.go:138 +0x4fa
  net/http.HandlerFunc.ServeHTTP()
      /usr/lib/go-1.9/src/net/http/server.go:1918 +0x51
  net/http.serverHandler.ServeHTTP()
      /usr/lib/go-1.9/src/net/http/server.go:2619 +0xbc
  net/http.(*conn).serve()
      /usr/lib/go-1.9/src/net/http/server.go:1801 +0x83b

Goroutine 23 (running) created at:
  github.com/tendermint/tendermint/consensus.(*ConsensusState).OnStart()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/state.go:250 +0x35b
  github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.(*BaseService).Start()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common/service.go:130 +0x5fc
  github.com/tendermint/tendermint/consensus.(*ConsensusReactor).OnStart()
      /home/vagrant/go/src/github.com/tendermint/tendermint/consensus/reactor.go:69 +0x1b4
  github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.(*BaseService).Start()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common/service.go:130 +0x5fc
  github.com/tendermint/tendermint/consensus.(*ConsensusReactor).Start()
      <autogenerated>:1 +0x43
  github.com/tendermint/tendermint/p2p.(*Switch).OnStart()
      /home/vagrant/go/src/github.com/tendermint/tendermint/p2p/switch.go:177 +0x124
  github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.(*BaseService).Start()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common/service.go:130 +0x5fc
  github.com/tendermint/tendermint/node.(*Node).OnStart()
      /home/vagrant/go/src/github.com/tendermint/tendermint/node/node.go:416 +0xa1b
  github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.(*BaseService).Start()
      /home/vagrant/go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common/service.go:130 +0x5fc
  github.com/tendermint/tendermint/rpc/test.StartTendermint()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/test/helpers.go:100 +0x5b
  github.com/tendermint/tendermint/rpc/client_test.TestMain()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/client/main_test.go:17 +0x4c
  main.main()
      github.com/tendermint/tendermint/rpc/client/_test/_testmain.go:76 +0x1cd

Goroutine 47 (running) created at:
  net/http.(*Server).Serve()
      /usr/lib/go-1.9/src/net/http/server.go:2720 +0x37c
  net/http.Serve()
      /usr/lib/go-1.9/src/net/http/server.go:2323 +0xe2
  github.com/tendermint/tendermint/rpc/lib/server.StartHTTPServer.func1()
      /home/vagrant/go/src/github.com/tendermint/tendermint/rpc/lib/server/http_server.go:35 +0xb3
```

* removed excessive comment

Refs https://github.com/tendermint/tendermint/pull/1446#discussion_r180353446

* use the tag interface for pubsub. (#1438)

* use the tag interface for pubsub.

* update tmlibs.

* Fix unresolved conflict.

* improve `show_node_id` (#1433)

* fix show_node_id

* make LoadNodeKey public

* make LoadNodeKey public

* remove if

* remove if