In preparation for removing redundant fields from the commit [\#1648](https://github.com/tendermint/tendermint/issues/1648)
### IMPROVEMENTS:
- [consensus] [\#3246](https://github.com/tendermint/tendermint/issues/3246) Better logging and notes on recovery for corrupted WAL file
- [crypto] [\#3163](https://github.com/tendermint/tendermint/issues/3163) Use ethereum's libsecp256k1 go-wrapper for signatures when cgo is available
- [crypto] [\#3162](https://github.com/tendermint/tendermint/issues/3162) Wrap btcd instead of forking it to keep up with fixes (used if cgo is not available)
- [makefile] [\#3233](https://github.com/tendermint/tendermint/issues/3233) Use golangci-lint instead of go-metalinter
- [tools] [\#3218](https://github.com/tendermint/tendermint/issues/3218) Add go-deadlock tool to help detect deadlocks
- [tools] [\#3106](https://github.com/tendermint/tendermint/issues/3106) Add tm-signer-harness test harness for remote signers
- [tests] [\#3258](https://github.com/tendermint/tendermint/issues/3258) Fixed a bunch of non-deterministic test failures
### BUG FIXES:
- [node] [\#3186](https://github.com/tendermint/tendermint/issues/3186) EventBus and indexerService should be started before first block (for replay last block on handshake) execution (@ackratos)
- [p2p] [\#3232](https://github.com/tendermint/tendermint/issues/3232) Fix infinite loop leading to addrbook deadlock for seed nodes
- [p2p] [\#3247](https://github.com/tendermint/tendermint/issues/3247) Fix panic in SeedMode when calling FlushStop and OnStop
concurrently
- [p2p] [\#3040](https://github.com/tendermint/tendermint/issues/3040) Fix MITM on secret connection by checking low-order points
- [privval] [\#3258](https://github.com/tendermint/tendermint/issues/3258) Fix race between sign requests and ping requests in socket