* follow up to removing some consensus params Refs #2382
* change args type to int64 in state#makeParams
* make valsCount and evidenceCount ints again
* MaxEvidenceBytesPerBlock: include magic number in godoc
* [spec] creating a proposal
* test state#TxFilter
* panic if MaxDataBytes is less than 0
* fixes after review
* use amino#UvarintSize to calculate overhead
0c74291f3b/encoder.go (L85-L90)
* avoid cyclic imports
* you can do better Go, come on
* remove testdouble package
* Make mempool aware of MaxGas requirement
* update spec
* Add tests
* Switch GasWanted from kv store to persistent kv store
* Fix typo in test name
* switch back to using kvstore, not persistent kv store
* #1920 try to fix race condition on proposal height for published txs
- related to create_empty_blocks=false
- published height for accepted tx can be wrong (too low)
- use the actual mempool height + 1 for the proposal
- expose Height() on mempool
* #1920 add initial test for mempool.Height()
- not sure how to test the lock
- can the mutex reference be of type Locker?
-- this way, we can use a "mock" of the mutex to test triggering
* #1920 use the ConsensusState height in favor of mempool
- gets rid of indirections
- doesn't need any "+1" magic
* #1920 cosmetic
- if we use cs.Height, it's enough to evaluate right before propose
* #1920 cleanup TODO and non-needed code
* #1920 add changelog entry
