Should fix #3295
Also partial fix of #3043

* changelog, upgrading, version

* update for evidence fixes

* linkify

* fix an entry

* remove MixEntropy

* changelog

* update changelog

* linkify

* bump version

* update main changelog

* final fixes

* entry for wal fix

* changelog preamble

* remove a line

* update changelog and upgrading

* add note about max voting power in abci spec

* update version

* changelog

* changelog pending and upgrading

* linkify and version bump

* changelog shuffle

* crypto: revert to mainline Go crypto lib

We used to use a fork for a modified bcrypt so we could pass our own
randomness but this was largely unecessary, unused, and a burden.
So now we just use the mainline Go crypto lib.

* changelog

* fix tests

* version and changelog

* makeNodeInfo returns error

* version and changelog

* update changelog

* linkify

* changelog and version

* p2p: test case for peer count mismatch #2332

* p2p: fix peer count mismatch #2332

* changelog

* use httptest.Server to scrape Prometheus metrics

* p2p: panic on transport error

Addresses #2823. Currently, the acceptRoutine exits if the transport returns
an error trying to accept a new connection. Once this happens, the node
can't accept any new connections. So here, we panic instead. While we
could potentially be more intelligent by rerunning the acceptRoutine, the
error may indicate something more fundamental (eg. file desriptor limit)
that requires a restart anyways. We can leave it to process managers to
handle that restart, and notify operators about the panic.

* changelog

* update changelog

* changelog, upgrading, version

* prepare changelog

* linkify changelog

* changelog and version

* update changelog

* update CONTRIBUTING with notes on CHANGELOG

* update changelog

* changelog and version

* add adr-034

* update changelog

* minor changes

* do some refactor

* changelog and version

* fix changelog

* Require addressbook to only store addresses with valid ID

* Do not shut down peer immediately after sending pex addrs in SeedMode

* p2p: fix #2773

* seed mode: use go-routine to sleep before stopping peer

* changelog_pending -> changelog

* update changelog

* update changelog

* update changelog and upgrading

* libs/autofile: bring back loops

* changelog, version

This now uses one hkdf on the X25519 shared secret to create
a key for the sender and receiver.
The hkdf call is now just called upon the computed shared
secret, since the shared secret is a function of the pubkeys.

The nonces now start at 0, as we are using chacha as a stream
cipher, and the sender and receiver now have different keys.

Generate keys with HKDF instead of hash functions, which provides better security properties.

Add xchacha20poly1305 to secret connection. (Due to rebasing, this code has been removed)

Refs #1706

before: 1.000000003s
after: 3.000000000s

Refs #2027

* update changelog

* txAvailable is always true

Refs #2021, #1920

* remove debug message

No additional value. `enterPropose` log message should be enough.

Refs #2021, #1920

* #1920 try to fix race condition on proposal height for published txs

- related to create_empty_blocks=false
- published height for accepted tx can be wrong (too low)
- use the actual mempool height + 1 for the proposal
- expose Height() on mempool

* #1920 add initial test for mempool.Height()

- not sure how to test the lock
- can the mutex reference be of type Locker?
-- this way, we can use a "mock" of the mutex to test triggering

* #1920 use the ConsensusState height in favor of mempool

- gets rid of indirections
- doesn't need any "+1" magic

* #1920 cosmetic

- if we use cs.Height, it's enough to evaluate right before propose

* #1920 cleanup TODO and non-needed code

* #1920 add changelog entry

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