This issue is related to #3107
This is a first renaming/refactoring step before reworking and removing heartbeats.
As discussed with @Liamsi , we preferred to go for a couple of independent and separate PRs to simplify review work.

The changes:

    Help to clarify the relation between the validator and remote signer endpoints
    Differentiate between timeouts and deadlines
    Prepare to encapsulate networking related code behind RemoteSigner in the next PR

My intention is to separate and encapsulate the "network related" code from the actual signer.

SignerRemote ---(uses/contains)--> SignerValidatorEndpoint <--(connects to)--> SignerServiceEndpoint ---> SignerService (future.. not here yet but would like to decouple too)

All reconnection/heartbeat/whatever code goes in the endpoints. Signer[Remote/Service] do not need to know about that.

I agree Endpoint may not be the perfect name. I tried to find something "Go-ish" enough. It is a common name in go-kit, kubernetes, etc.

Right now:
SignerValidatorEndpoint:

    handles the listener
    contains SignerRemote
    Implements the PrivValidator interface
    connects and sets a connection object in a contained SignerRemote
    delegates PrivValidator some calls to SignerRemote which in turn uses the conn object that was set externally

SignerRemote:

    Implements the PrivValidator interface
    read/writes from a connection object directly
    handles heartbeats

SignerServiceEndpoint:

    Does most things in a single place
    delegates to a PrivValidator IIRC.

* cleanup

* Refactoring step 1

* Refactoring step 2

* move messages to another file

* mark for future work / next steps

* mark deprecated classes in docs

* Fix linter problems

* additional linter fixes

* make govet linter pass

Refs #3262

* close PipeReader and check for err

* privval: more info in errors

* wal: change Debug logs to Info

* wal: log and return error on corrupted wal instead of panicing

* fail: Exit right away instead of sending interupt

* consensus: FAIL before handling our own vote

allows to replicate #3089:
- run using `FAIL_TEST_INDEX=0`
- delete some bytes from the end of the WAL
- start normally

Results in logs like:

```
I[2019-02-03|18:12:58.225] Searching for height module=consensus wal=/Users/ethanbuchman/.tendermint/data/cs.wal/wal height=1 min=0 max=0
E[2019-02-03|18:12:58.225] Error on catchup replay. Proceeding to start ConsensusState anyway module=consensus err="failed to read data: EOF"
I[2019-02-03|18:12:58.225] Started node module=main nodeInfo="{ProtocolVersion:{P2P:6 Block:9 App:1} ID_:35e87e93f2e31f305b65a5517fd2102331b56002 ListenAddr:tcp://0.0.0.0:26656 Network:test-chain-J8JvJH Version:0.29.1 Channels:4020212223303800 Moniker:Ethans-MacBook-Pro.local Other:{TxIndex:on RPCAddress:tcp://0.0.0.0:26657}}"
E[2019-02-03|18:12:58.226] Couldn't connect to any seeds module=p2p
I[2019-02-03|18:12:59.229] Timed out module=consensus dur=998.568ms height=1 round=0 step=RoundStepNewHeight
I[2019-02-03|18:12:59.230] enterNewRound(1/0). Current: 1/0/RoundStepNewHeight module=consensus height=1 round=0
I[2019-02-03|18:12:59.230] enterPropose(1/0). Current: 1/0/RoundStepNewRound module=consensus height=1 round=0
I[2019-02-03|18:12:59.230] enterPropose: Our turn to propose module=consensus height=1 round=0 proposer=AD278B7767B05D7FBEB76207024C650988FA77D5 privValidator="PrivValidator{AD278B7767B05D7FBEB76207024C650988FA77D5 LH:1, LR:0, LS:2}"
E[2019-02-03|18:12:59.230] enterPropose: Error signing proposal module=consensus height=1 round=0 err="Error signing proposal: Step regression at height 1 round 0. Got 1, last step 2"
I[2019-02-03|18:13:02.233] Timed out module=consensus dur=3s height=1 round=0 step=RoundStepPropose
I[2019-02-03|18:13:02.233] enterPrevote(1/0). Current: 1/0/RoundStepPropose module=consensus
I[2019-02-03|18:13:02.233] enterPrevote: ProposalBlock is nil module=consensus height=1 round=0
E[2019-02-03|18:13:02.234] Error signing vote module=consensus height=1 round=0 vote="Vote{0:AD278B7767B0 1/00/1(Prevote) 000000000000 000000000000 @ 2019-02-04T02:13:02.233897Z}" err="Error signing vote: Conflicting data"
```

Notice the EOF, the step regression, and the conflicting data.

* wal: change errors to be DataCorruptionError

* exit on corrupt WAL

* fix log

* fix new line

* Close and recreate a RemoteSigner on err

* Update changelog

* Address Anton's comments / suggestions:

 - update changelog
 - restart TCPVal
 - shut down on `ErrUnexpectedResponse`

* re-init remote signer client with fresh connection if Ping fails

- add/update TODOs in secret connection
- rename tcp.go -> tcp_client.go, same with ipc to clarify their purpose

* account for `conn returned by waitConnection can be `nil`

- also add TODO about RemoteSigner conn field

* Tests for retrying: IPC / TCP

 - shorter info log on success
 - set conn and use it in tests to close conn

* Tests for retrying: IPC / TCP

 - shorter info log on success
 - set conn and use it in tests to close conn
 - add rwmutex for conn field in IPC

* comments and doc.go

* fix ipc tests. fixes #2677

* use constants for tests

* cleanup some error statements

* fixes #2784, race in tests

* remove print statement

* minor fixes from review

* update comment on sts spec

* cosmetics

* p2p/conn: add failing tests

* p2p/conn: make SecretConnection thread safe

* changelog

* IPCVal signer refactor

- use a .reset() method
- don't use embedded RemoteSignerClient
- guard RemoteSignerClient with mutex
- drop the .conn
- expose Close() on RemoteSignerClient

* apply IPCVal refactor to TCPVal

* remove mtx from RemoteSignerClient

* consolidate IPCVal and TCPVal, fixes #3104

- done in tcp_client.go
- now called SocketVal
- takes a listener in the constructor
- make tcpListener and unixListener contain all the differences

* delete ipc files

* introduce unix and tcp dialer for RemoteSigner

* rename files

- drop tcp_ prefix
- rename priv_validator.go to file.go

* bring back listener options

* fix node

* fix priv_val_server

* fix node test

* minor cleanup and comments

* split immutable and mutable parts of priv_validator.json

* fix bugs

* minor changes

* retrig test

* delete scripts/wire2amino.go

* fix test

* fixes from review

* privval: remove mtx

* rearrange priv_validator.go

* upgrade path

* write tests for the upgrade

* fix for unsafe_reset_all

* add test

* add reset test

* 2871 remove proposalHeartbeat infrastructure

* 2871 add preliminary changelog entry

* catch up with amino changes in
https://github.com/tendermint/go-amino/pull/222

* WIP: update to amino v0.13.0

* update to fixed amino release

* WIP: switching to fixed offsets for SignBytes

* add version field to sign bytes and update order

* more comments on test-cases and add a tc with a chainID

* remove amino:"write_empty" tag

- it doesn't affect if default fixed size fields ((u)int64) are
written or not
- add comment about int->int64 casting

* update CHANGELOG_PENDING

* update documentation

* add back link to issue #1622 in documentation

* remove JSON tags and add (failing test-case)

* fix failing test

* update test-vectors due to added `Type` field

* change Type field from string to byte and add new type alias

- SignedMsgType replaces VoteTypePrevote, VoteTypePrecommit and adds new
ProposalType to separate votes from proposal when signed

- update test-vectors

* fix remains from rebasing

* use SignMessageType instead of byte everywhere

* fixes from review

* remove some XXX

* config: remove Mempool.RecheckEmpty

* docs: remove recheck_empty

* 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

* Implement BFT time

* set LastValidators when creating state in state helper

for heights >= 2

* libs: Remove usage of custom Fmt, in favor of fmt.Sprintf

Closes #2193

* Fix bug that was masked by custom Fmt!

Signatures are now []byte, which saves on the number of bytes after
amino encoding

(squash this) address Ismail's comment

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.

Closes #1829

except now we calculate the max size using the maxPacketMsgSize()
function, which frees developers from having to know amino encoding
details.

plus, 10 additional bytes are added to leave the room for amino upgrades
(both making it more efficient / less efficient)

This reverts commit 96a3502

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