* VM BALANCE opcode updated to pop 1 item and use that to retrieve the
  address' balance
* GetBalance and GetNonce on state that'll always return something valid

* Ensure that each state object has an address that is 20 bytes
* Byte logging for vm
* changed diff output

Revert "ethreact - Feature/ethutil refactor"

ethreact - Feature/ethutil refactor

- introduce quit, drained, shutdown channels
- mainLoop falls through reading message channel to drained state, and waits is blocked in default branch until any message is sent
- Flush() waits for <-drained
- Stop() pushes quit and nodges mainloop out of blocking drained state
- package-global mutex
- Reset()
- clear tests

- consistent renaming
- React -> Event
- ReactorEvent -> EventHandler
- NewReactorEngine -> New
- async ReactorEngine main loop with select on main eventChannel and quit channel
- ReactorEngine main loop control with Start() Stop() Flush()
- ReactorEngine.dispatch
- use sync.RWMutex
- delete eventHandler if subscribed channels go to 0