refactored path following to be an action
units now follow the path
Merge branch 'towerdefense' of https://github.com/duke-compsci308-spring2013/vooga into towerdefense

Conflicts:
	src/vooga/towerdefense/action/Action.java
	src/vooga/towerdefense/action/Move.java
	src/vooga/towerdefense/factories/ExampleUnitFactory.java
	src/vooga/towerdefense/gameElements/Unit.java