Added handler() and action() to AchieveREResponder
Removed verification of Context type

It wasn't working, and there's nothing serious about it, because
everything works the same if the context is a normal Collection,
except that agents stop being recognized by Repast.
Implemented the AchieveRE protocol (still work in progress)

Turns out that whoever implements these protocols is forced to
redefine the annotations in the action method, even when not overriding
the method!
Tests with this implementation showed that the messages are being
passed along via the MTS. The behaviors still lack the prepareRequest
methods etc.