Update to latest RSpec and GraphViz
Remove transitioning with state!, make events act like transition

* Transitioning with state! no longer works
* Transitioning with event is analogous to transition
* Transitioning with event! is analogous to transition!
* Renamed StateMachine private methods
Remove deprecated Finalizer references
Use InvalidTransition instead of both UnknownTransition and InvalidEvent
Update README for error changes
Merge pull request #14 from Originate/transition-shortcut-breaking-changes

Transition shortcut breaking changes