also, make running Prometheus server optional.

Closes #2019

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

* 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 reverts commit 58d0c8de89.

This reverts commit d02c5d1e30.

* limit the number of requests in flights for Prometheus server

Closes #1804

Default to 1 because usually there's just one collector.

* config: Up default for prom connections

* 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

* update changelog

* document p2p/listener

* do not expose underlying net.Listener

* add a TODO

* replace todo with a comment

* 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

Refs #1740

also, expose limit option for number concurrent streams for gRPC
(unlimited by default)

This reverts commit 96a3502

- move prometheus metrics into internal packages
- *Option structs
- misc. format changes

we don't really need to export it

This is a maintenance change to move the private validator package out
of the types and to a top-level location. There is no good reason to
keep it under the types and it will more clearly coommunicate where
additions related to the privval belong. It leaves the interface and the
mock in types for now as it would introduce circular dependency between
privval and types, this should be resolved eventually.

* mv priv_validator to privval pkg
* use consistent `privval` as import

Follow-up to #1255

As we didn't hear any voices requesting this feature, we removed the
option to disable it and always have peer connection auth encrypted.

closes #1518
follow-up #1325

should fix #1199

* 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