consensus fixes

gistfile1.txt

* state/execution.go
 - // ApplyBlock executes the block, then commits and updates the mempool atomically
   becomes...
   // ApplyBlock executes the block, updates state w/ ABCI responses, then commits and updates the mempool atomically, then saves state
 - execBlockOnProxyApp should return relevant ABCI responses
 - Between s.ExecBlock and s.CommitStateUpdateMempool, add a function to save ABI responses, 's.SaveABCIResponses'. Make the ABCI responses a simple field of state.State. Make it a pointer, and have State.Copy() just copy the pointer -- ABCI responses are not mutable.
 - Move call to 's.SetBlockAndValidators' to between s.SaveABCIResponses and s.CommitStateUpdateMempool.  Also move calls to 'updateValidators' and 'IncrementAccum' into s.SetBlockAndValidators.  Change s.SetBlockAndValidators to include ABCI responses as arguments.
 - After s.CommitStateUpdateMempool, save the state.
* In state/state.go
 - Change 'updated at end of ExecBlock' to 'updated at end of SetBlockAndValidators'
* In consensus/state.go
 - Before ApplyBlock, write #ENDHEIGHT to wal.  And remove #HEIGHT auto-writer from consensus/wal.go
 - Remove stateCopy.Save()
 - BTW, we should also remove 'TODO: Handle app failure.  See #177' and close #177. In the future, MultiAppConn should take care of it transparenty.
* In blockchain/reactor.go
 - Remove bcR.state.Save()
* In consensus/replay.go
 - Remove 'h.replayLastBlock' from `if appBlockHeight == stateBlockHeight`
 - Revert timeout logic in 'replayLastBlock'
 - Replace 'h.replayLastBlock' from `if appBlockHeight == storeBlockHeight`
   Replace it with `state.ApplyBlock()` but using the mockApp.
 - Make newMockProxyApp() take the stored ABCI responses in addition to the app hash
 - Search for #ENDHEIGHT rather than #HEIGHT in both places (and decrement the argument by 1)