Special thanks to external contributors on this release: @jon-certik
Special thanks to external contributors on this release: @jon-certik, @gracenoah
Friendly reminder, we have a [bug bounty
program](https://hackerone.com/tendermint).
### BREAKING CHANGES:
- CLI/RPC/Config
- [rpc] [\#3984](https://github.com/tendermint/tendermint/issues/3984) Add `MempoolClient` interface to `Client` interface
### IMPROVEMENTS:
- [rpc] [\#2010](https://github.com/tendermint/tendermint/issues/2010) Add NewHTTPWithClient and NewJSONRPCClientWithHTTPClient (note these and NewHTTP, NewJSONRPCClient functions panic if remote is invalid) (@gracenoah)
- [rpc] [\#3984](https://github.com/tendermint/tendermint/issues/3984) Add `MempoolClient` interface to `Client` interface
- [rpc] [\#3882](https://github.com/tendermint/tendermint/issues/3882) Add custom marshalers to proto messages to disable `omitempty`