* WIP: Starts adding remote signer test harness

This commit adds a new command to Tendermint to allow for us to build a
standalone binary to test remote signers such as KMS
(https://github.com/tendermint/kms).

Right now, all it does is test that the local public key matches the
public key reported by the client, and fails at the point where it
attempts to get the client to sign a proposal.

* Fixes typo

* Fixes proposal validation test

This commit fixes the proposal validation test as per #3149. It also
moves the test harness into its own internal package to isolate its
exports from the `privval` package.

* Adds vote signing validation

* Applying recommendations from #3149

* Adds function descriptions for test harness

* Adds ability to ask remote signer to shut down

Prior to this commit, the remote signer needs to manually be shut down,
which is not ideal for automated testing. This commit allows us to send
a poison pill message to the KMS to let it shut down gracefully once
testing is done (whether the tests pass or fail).

* Adds tests for remote signer test harness

This commit makes some minor modifications to a few files to allow for
testing of the remote signer test harness. Two tests are added here:
checking for a fully successful (the ideal) case, and for the case where
the maximum number of retries has been reached when attempting to accept
incoming connections from the remote signer.

* Condenses serialization of proposals and votes using existing Tendermint functions

* Removes now-unnecessary amino import and codec

* Adds error message for vote signing failure

* Adds key extraction command for integration test

Took the code from here:
https://gist.github.com/Liamsi/a80993f24bff574bbfdbbfa9efa84bc7 to
create a simple utility command to extract a key from a local Tendermint
validator for use in KMS integration testing.

* Makes path expansion success non-compulsory

* Fixes segfault on SIGTERM

We need an additional variable to keep track of whether we're
successfully connected, otherwise hitting Ctrl+Break during execution
causes a segmentation fault. This now allows for a clean shutdown.

* Consolidates shutdown checks

* Adds comments indicating codes for easy lookup

* Adds Docker build for remote signer harness

Updates the `DOCKER/build.sh` and `DOCKER/push.sh` files to allow one to
override the image name and Dockerfile using environment variables.
Updates the primary `Makefile` as well as the `DOCKER/Makefile` to allow
for building the `remote_val_harness` Docker image.

* Adds build_remote_val_harness_docker_image to .PHONY

* Removes remote signer poison pill messaging functionality

* Reduces fluff code in command line parsing

As per
https://github.com/tendermint/tendermint/pull/3149#pullrequestreview-196171788,
this reduces the amount of fluff code in the PR down to the bare
minimum.

* Fixes ordering of error check and info log

* Moves remove_val_harness cmd into tools folder

It seems to make sense to rather keep the remote signer test harness in
its own tool folder (now rather named `tm-signer-harness` to keep with
the tool naming convention). It is actually a separate tool, not meant
to be one of the core binaries, but supplementary and supportive.

* Updates documentation for tm-signer-harness

* Refactors flag parsing to be more compact and less redundant

* Adds version sub-command help

* Removes extraneous flags parsing

* Adds CHANGELOG_PENDING entry for tm-signer-harness

* Improves test coverage

Adds a few extra parameters to the `MockPV` type to fake broken vote and
proposal signing. Also adds some more tests for the test harness so as
to increase coverage for failed cases.

* Fixes formatting for CHANGELOG_PENDING.md

* Fix formatting for documentation config

* Point users towards official Tendermint docs for tools documentation

* Point users towards official Tendermint docs for tm-signer-harness

* Remove extraneous constant

* Rename TestHarness.sc to TestHarness.spv for naming consistency

* Refactor to remove redundant goroutine

* Refactor conditional to cleaner switch statement and better error handling for listener protocol

* Remove extraneous goroutine

* Add note about installing tmkms via Cargo

* Fix typo in naming of output signing key

* Add note about where to find chain ID

* Replace /home/user with ~/ for brevity

* Fixes "signer.key" typo

* Minor edits for clarification for tm-signer-harness bulid/setup process

privval: remove GetAddress(), memoize pubkey

* 2871 remove proposalHeartbeat infrastructure

* 2871 add preliminary changelog entry

* switch to amino for SignBytes and add Reply with error message

- currently only Vote is done

* switch Reply type in socket for other messages

 - add error description on error

* add TODOs regarding error handling

* address comments from peer review session (thx @xla)

 - contains all changes besides the test-coverage / error'ing branches

* increase test coverage:

 - add tests for each newly introduced error'ing code path

* return error if received wrong response

* add test for wrong response branches (ErrUnexpectedResponse)

* update CHANGELOG_PENDING and related documentation (spec)

* fix typo: s/CanonicallockID/CanonicalBlockID

* fixes from review

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

This reverts commit 58d0c8de89.

This reverts commit d02c5d1e30.

- re-add test
- add TODO
- err instead of panic where possible

This reverts commit 96a3502

* use increment and decrement operators.

* remove unnecessary else branches.

* fix package comment with leading space.

* fix receiver names.

* fix error strings.

* remove omittable code.

* remove redundant return statement.

* Revert changes (code is generated.)

* use cfg as receiver name for all config-related types.

* use lsi as the receiver name for the LastSignedInfo type.

* expose AuthEnc in the P2P config

if AuthEnc is true, dialed peers must have a node ID in the address and
it must match the persistent pubkey from the secret handshake.

Refs #1157

* fixes after my own review

* fix docs

* fix build failure

```
p2p/pex/pex_reactor_test.go:288:88: cannot use seed.NodeInfo().NetAddress() (type *p2p.NetAddress) as type string in array or slice literal
```

* p2p: introduce peerConn to simplify peer creation

* Introduce `peerConn` containing the known fields of `peer`
* `peer` only created in `sw.addPeer` once handshake is complete and NodeInfo is checked
* Eliminates some mutable variables and makes the code flow better
* Simplifies the `newXxxPeer` funcs
* Use ID instead of PubKey where possible.
        * SetPubKeyFilter -> SetIDFilter
        * nodeInfo.Validate takes ID
        * remove peer.PubKey()

* persistent node ids

* fixes from review

* test: use ip_plus_id.sh more

* fix invalid memory panic during fast_sync test

```
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: panic: runtime error: invalid memory address or nil pointer dereference
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: [signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0x98dd3e]
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]:
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: goroutine 3432 [running]:
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: github.com/tendermint/tendermint/p2p.newOutboundPeerConn(0xc423fd1380, 0xc420933e00, 0x1, 0x1239a60, 0
xc420128c40, 0x2, 0x42caf6, 0xc42001f300, 0xc422831d98, 0xc4227951c0, ...)
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: #011/go/src/github.com/tendermint/tendermint/p2p/peer.go:123 +0x31e
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: github.com/tendermint/tendermint/p2p.(*Switch).addOutboundPeerWithConfig(0xc4200ad040, 0xc423fd1380, 0
xc420933e00, 0xc423f48801, 0x28, 0x2)
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: #011/go/src/github.com/tendermint/tendermint/p2p/switch.go:455 +0x12b
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: github.com/tendermint/tendermint/p2p.(*Switch).DialPeerWithAddress(0xc4200ad040, 0xc423fd1380, 0x1, 0x
0, 0x0)
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: #011/go/src/github.com/tendermint/tendermint/p2p/switch.go:371 +0xdc
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: github.com/tendermint/tendermint/p2p.(*Switch).reconnectToPeer(0xc4200ad040, 0x123e000, 0xc42007bb00)
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: #011/go/src/github.com/tendermint/tendermint/p2p/switch.go:290 +0x25f
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: created by github.com/tendermint/tendermint/p2p.(*Switch).StopPeerForError
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: #011/go/src/github.com/tendermint/tendermint/p2p/switch.go:256 +0x1b7
```

As calls to the private validator can involve side-effects like network
communication it is desirable for all methods returning an error to not
break the control flow of the caller.

* adjust PrivValidator interface

NOTE we only updating for tmlibs and abci

* Vulnerability in light client proxy

When calling GetCertifiedCommit the light client proxy would call
Certify and even on error return the Commit as if it had been correctly
certified.

Now it returns the error correctly and returns an empty Commit on error.

* Improve names for clarity

The lite package now contains StaticCertifier, DynamicCertifier and
InqueringCertifier. This also changes the method receivers from one
letter to two letter names, which will make future refactoring easier
and follows the coding standards.

* Fix test failures

* Rename files

* remove dead code

since now we have time in the msgs and we might crash between writing
the priv val and writing to wal.

Refs #984

uint64 is considered dangerous. the details will follow in a blog post.

Users can now just pass an object that implements the Signer interface.

Prior to this change, a custom Signer would have no knowledge of the private
key stored in the configuration file. This changes introduces a generator
function, which creates a Signer based on the private key. This provides an
opportunity for customer Signers to adjust behaviour based on the key
contents. (E.g. imagine key contents are a key label, rather than the key
itself).

This change allows the default privValidator to use a custom Signer
implementation with no reliance on the default Signer implementation.

By exporting all of the commands, we allow users to setup their own
tendermint node cli. This enables users to provide a different
pivValidator without the need to fork tendermint.