previously, the second next could return nil, which would be the reason
for panic on line 275:

memTx := next.Value.(*mempoolTx)

Closes #5408

Closes #5339

Closes #2589

## Description

Add information on p2p settings in documentation 

Closes: #XXX

## Description

Add simple `NoBlockResponse` handling to blockchain reactor v1. I tested before and after with erik's e2e testing and was not able to reproduce the inability to sync after the changes were applied

Closes: #5394

* docs: fix /validators description

Refs https://github.com/tendermint/spec/pull/169

* consensus: remove nil err from logging statement

* update UPGRADING.md

* note about LightBlocks

This change adds some polish to the upgrading instructions for 0.34. The only substantive changes include:
* Calling out ABCI-impacting changes explicitly in the "ABCI Changes" section, even if those changes are also mentioned elsewhere
* Removes `ProofOfTrialPeriod` from consensus params; this change was introduced and then removed.

Reduces the state sync discovery time from 20 to 15 seconds, and makes it configurable.

This caused the node to crash whenever any state sync-related request was called via the ABCI UNIX socket client.

Bumps [vuepress-theme-cosmos](https://github.com/cosmos/vuepress-theme-cosmos) from 1.0.172 to 1.0.173.
- [Release notes](https://github.com/cosmos/vuepress-theme-cosmos/releases)
- [Commits](https://github.com/cosmos/vuepress-theme-cosmos/commits)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Tess Rinearson <tess.rinearson@gmail.com>

Cleans up the grammar, removes out-of-date information, and reduces false promises.

Clean up some inconsistent formatting and missing PR numbers.

Closes #625

also, document consensus parameters.
https://forum.cosmos.network/t/consensus-timeouts-explained/1421

Closes #4489

Fixes #5377 and comments in #4588 (review).

Closes #5145

also applies to light/client

## Description

Add a cmd to docker image and use it to format our proto files. This avoids developers the need to install clang-format

Closes: #XXX

found out this issue when trying to decouple mempool reactor with its
underlying clist implementation.

according to its comment, the test `TestReactorNoBroadcastToSender` is
intended to make sure that a peer shouldn't send tx back to its origin.
however, the current test forgot to init peer state key, thus the code
will get stuck at waiting for peer to catch up state *instead of* skipping
sending tx back:

b8d08b9ef4/mempool/reactor.go (L216-L226)

this PR fixes the issue by init peer state key.

evidence: modify evidence types (#5342)

light: detect light client attacks (#5344)

evidence: refactor evidence pool (#5345)

abci: application evidence prepared by evidence pool (#5354)

Revert the JSON-RPC/WebSocket response serialization format to the
standard way (i.e. a single RPC response per WebSocket text message) to
avoid breaking clients.

Serialization format changes will be discussed in an upcoming ADR.

Closes: #5373

[Rendered](https://github.com/tendermint/tendermint/blob/erik/adr-api-stability/docs/architecture/adr-059-go-api-stability.md)

Bumps [github.com/minio/highwayhash](https://github.com/minio/highwayhash) from 1.0.0 to 1.0.1.
- [Release notes](https://github.com/minio/highwayhash/releases)
- [Commits](https://github.com/minio/highwayhash/compare/v1.0.0...v1.0.1)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

## Description

Adding a section explaining the state store interface change. I wasn't aware this was used externally. Our infamous API strikes again.


<img width="462" alt="Screen Shot 2020-09-16 at 2 57 12 PM" src="https://user-images.githubusercontent.com/24299864/93342053-2835fe80-f82f-11ea-9296-9484c2931d9a.png">

Closes: #XXX

Fixes a couple of test data races. `testing.T` is not concurrency-safe and should not be used in goroutines at all.

Broke in #5356.

## Description

This PR adds support for badgerdb, rocksdb and boltdb within the build options. 

RocksDB builds correctly.

```
 make build TENDERMINT_BUILD_OPTIONS=rocksdb    
CGO_ENABLED=1 go build -mod=readonly -ldflags "-X github.com/tendermint/tendermint/version.GitCommit=`git rev-parse --short=8 HEAD` -s -w " -trimpath -tags 'tendermint rocksdb' -o build/tendermint ./cmd/tendermint/

tendermint on  master [$!] via 🐹 v1.15.2 took 19s 
```

Closes: #5355

Closes #5339

## Description

Make an interface for the state store. 

Closes: #5213

## Description

Hide the RFC section from the docs website. 

Closes: #XXX

## Description

Add a sentence on `initial_height`.

There will be a section in the spec repo explaining the genesis more in depth as this is something that will affect both clients

Closes: #XXX

## Description

Reword the readme of the crypto package. 

Closes: #XXX

[Rendered](https://github.com/tendermint/tendermint/blob/erik/rfc-e2e-testing/docs/rfc/rfc-001-end-to-end-testing.md).

Related to #5291.

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.31.1 to 1.32.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.31.1...v1.32.0)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

## Description

This PR aims to reduce the amount of `Logger.Error(..)` calls. Many of these calls are benign and do not need any intervention. 

Went from: 
```
node1    | E[2020-09-08|14:32:48.407] Connection failed @ recvRoutine (reading byte) module=p2p peer=af8747a81383f40583ae8790d2cc1f92cc7e4a35@192.167.10.4:26656 conn=MConn{192.167.10.4:26656} err="read tcp 192.167.10.3:48614->192.167.10.4:26656: read: connection reset by peer"
node1    | E[2020-09-08|14:32:48.407] Stopping peer for error                      module=p2p peer="Peer{MConn{192.167.10.4:26656} af8747a813 out}" err="read tcp 192.167.10.3:48614->192.167.10.4:26656: read: connection reset by peer"
node1    | E[2020-09-08|14:32:48.407] Error while stopping peer                    module=p2p peer=af8747a81383f40583ae8790d2cc1f92cc7e4a35@192.167.10.4:26656 err="already stopped"
node1    | E[2020-09-08|14:32:48.408] MConnection flush failed                     module=p2p peer=af8747a81383f40583ae8790d2cc1f92cc7e4a35@192.167.10.4:26656 err="write tcp 192.167.10.3:48614->192.167.10.4:26656: use of closed network connection"
```
To: 
```
node1    | E[2020-09-08|14:42:54.023] Stopping peer for error                      module=p2p peer="Peer{MConn{192.167.10.5:37844} e3d01d1795 in}" err=EOF
```

Closes: #4937

## Description

Check block protocol version in header validate basic. 

I tried searching for where we check the P2P protocol version but was unable to find it. When we check compatibility with a node we check we both have the same block protocol and are on the same network, but we do not check if we are on the same P2P protocol. It makes sense if there is a handshake change because we would not be able to establish a secure connection, but a p2p protocol version bump may be because of a p2p message change, which would go unnoticed until that message is sent over the wire.  Is this purposeful?

Closes: #4790

## Description

Enable errcheck linter throughout the codebase

Closes: #5059