* docs: explain create_empty_blocks configurations
Closes#3307
* Vagrantfile: install nodejs for docs
* update docs instructions
npm install does not make sense since there's no packages.json file
* explain broadcast_tx_* tx format
Closes#536
* docs: explain how transaction ordering works
Closes#2904
* bring in consensus parameters explained
* example for create_empty_blocks_interval
* bring in explanation from https://github.com/tendermint/tendermint/issues/2487#issuecomment-424899799
* link to formatting instead of duplicating info
* 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
* mempool: Store txs by hash inside of cache
This allows for large cachesizes, without fear of the memory
consumption growing rapidly.
* (squash this) rename hashedTx -> txHash
