Updated combabtant function
Added junits
added Turret and Structure test classes, and also fixed the original
classes
Merge remote-tracking branch 'Austin/master'
Finished Model Classes
Models are now finished. Refactored to match round 3 uml diagram. 
Main change is that interactable now implements Attackable
Commenteded Model Constructors
Implemented UnitTest and CombatantTest junit test classes

Currently there is a Class Cast Exception in UnitTest at line 42, which
adds a second waypoint to the PriorityQueue of waypoints.