Add early 'return super' to method_missing.

We only want to process {state} and {event} method calls that end with
either '?' or '!'. If we don't see that, we immediately super out, so
the wrapped object can handle the method.
Includes a unit spec to verify the correct behavior.
Merge pull request #7 from Originate/fix_method_missing_non_states_or_events

Add early 'return super' to method_missing.