This pull request merges in the changes for implementing Proposer-based timestamps into `master`. The power was primarily being done in the `wb/proposer-based-timestamps` branch, with changes being merged into that branch during development. This pull request represents an amalgamation of the changes made into that development branch. All of the changes that were placed into that branch have been cleanly rebased on top of the latest `master`. The changes compile and the tests pass insofar as our tests in general pass.

### Note To Reviewers
 These changes have been extensively reviewed during development. There is not much new here. In the interest of making effective use of time, I would recommend against trying to perform a complete audit of the changes presented and instead examine for mistakes that may have occurred during the process of rebasing the changes. I gave the complete change set a first pass for any issues, but additional eyes would be very appreciated. 

In sum, this change set does the following:
closes #6942 
merges in #6849

There are no further uses of this package anywhere in Tendermint.
All the uses in the Cosmos SDK are for types that now work correctly with the
standard encoding/json package.

## Description

Internalize some libs. This reduces the amount ot public API tendermint is supporting. The moved libraries are mainly ones that are used within Tendermint-core.

Fixes #5276.

Closes #2743

Refs #4926

* test-vectors for backwards compatibility:

 - copy & paste test-vectors from v0.33.5 to ensure
 backwards compatibility for vote's SignBytes

* WIP: everything besides time seems to match :-/

* almost

* Found the culprit: field nums weren't consecutive ints ...

* fix order of partset header too

* this last votes-related test can easily be fixed

* some minor changes and fix last failing test

* move proto types back to stdtime, fix various linting

* use libs/protoio

* remvoe commented code

* add comments

* fix tests

* uncomment testscases

* dont ignore error panic

* fix signable test

* fix happy path testing

* fix comment

Co-authored-by: Marko Baricevic <marbar3778@yahoo.com>

## Description

these proto files are meant to help unblock ibc in their quest of migrating the ibc module to proto.

Closes: #XXX

* libs/common: Refactor libs/common 4

- move byte function out of cmn to its own pkg
- move tempfile out of cmn to its own pkg
- move throttletimer to its own pkg

ref #4147

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* add changelog entry

* fix linting issues

Refs #3262

* Consistent order fields of Timestamp/BlockID fields in CanonicalVote and
CanonicalProposal

* update spec too

* Introduce and use IsZero & IsComplete:
 - update IsZero method according to spec and introduce IsComplete
 - use methods in validate basic to validate: proposals come with a
 "complete" blockId and votes are either complete or empty
 - update spec: BlockID.IsNil() -> BlockID.IsZero() and fix typo

* BlockID comes first

* fix tests

* validate reactor messages

Refs #2683

* validate blockchain messages

Refs #2683

* validate evidence messages

Refs #2683

* todo

* check ProposalPOL and signature sizes

* add a changelog entry

* check addr is valid when we add it to the addrbook

* validate incoming netAddr (not just nil check!)

* fixes after Bucky's review

* check timestamps

* beef up block#ValidateBasic

* move some checks into bcBlockResponseMessage

* update Gopkg.lock

Fix

```
grouped write of manifest, lock and vendor: failed to export github.com/tendermint/go-amino: fatal: failed to unpack tree object 6dcc6ddc14
```

by running `dep ensure -update`

* bump year since now we check it

* generate test/p2p/data on the fly using tendermint testnet

* allow sync chains older than 1 year

* use full path when creating a testnet

* move testnet gen to test/docker/Dockerfile

* relax LastCommitRound check

Refs #2737

* fix conflicts after merge

* add small comment

* some ValidateBasic updates

* fixes

* AppHash length is not fixed

* Align Proposal message with spec

* Update spec

* reorder fields

* add TestVoteString & update tests

* remove redundant info from Proposal.String()

* update spec

* revert changes on vote.String() -> more human friendly

* 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

* 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

- use cmn.Fingerprint and %X

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

(squash this) address Ismail's comment

This reverts commit d02c5d1e30.

Also, fix consensus liveness issue.

This reverts commit 96a3502

Store it as time.Timestamp locally, encode it as RFC3339 with milliseconds
before signing the canonical form.

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