* base verifier: bc->bv and check chainid
* improve some comments
* comments in dynamic verifier
* fix comment in doc about BaseVerifier
It requires the validator set to perfectly match.
* failing test for #2862
* move errTooMuchChange to types. fixes#2862
* changelog, comments
* ic -> dv
* update comment, link to issue
* Disable transitioning to new round upon 2/3+ of Precommit nils
Pull in ensureVote test function from https://github.com/tendermint/tendermint/pull/2132
* Add several ensureX test methods to wrap channel read with timeout
* Revert panic in tests
* Implement issues 2386: add synchronization in lite verify and change all Certify to Verify
* Replace make(chan struct{}, 0) with make(chan struct{})
* Parameterize memroy cache size and add concurrent test
* Refactor import order
