* execCommitBlock should not read from state.lastValidators

* fix height 1

* fix blockchain/reactor_test

* fix consensus/mempool_test

* fix consensus/reactor_test

* fix consensus/replay_test

* add CHANGELOG

* fix consensus/reactor_test

* fix consensus/replay_test

* add a test for replay validators change

* fix mem_pool test

* fix byzantine test

* remove a redundant code

* reduce validator change blocks to 6

* fix

* return peer0 config

* seperate testName

* seperate testName 1

* seperate testName 2

* seperate app db path

* seperate app db path 1

* add a lock before startNet

* move the lock to reactor_test

* simulate just once

* try to find problem

* handshake only saveState when app version changed

* update gometalinter to 3.0.0 (#3233)

in the attempt to fix https://circleci.com/gh/tendermint/tendermint/43165

also

    code is simplified by running gofmt -s .
    remove unused vars
    enable linters we're currently passing
    remove deprecated linters
(cherry picked from commit d47094550315c094512a242445e0dde24b5a03f5)

* gofmt code

* goimport code

* change the bool name to testValidatorsChange

* adjust receive kvstore.ProtocolVersion

* adjust receive kvstore.ProtocolVersion 1

* adjust receive kvstore.ProtocolVersion 3

* fix merge execution.go

* fix merge develop

* fix merge develop 1

* fix run cleanupFunc

* adjust code according to reviewers' opinion

* modify the func name match the convention

* simplify simulate a chain containing some validator change txs 1

* test CI error

* Merge remote-tracking branch 'upstream/develop' into fixReplay 1

* fix pubsub_test

* subscribeUnbuffered vote channel