merged numerical attributes with stat
merged numerical attribute with stat class
Formatted AttributeManager toString
minor commenting changes
Merge branch 'towerdefense' of https://github.com/duke-compsci308-spring2013/vooga into towerdefense
Added new ways to create an XML file.

Still needs improvement!
controller refactored
Merge branch 'towerdefense' of https://github.com/duke-compsci308-spring2013/vooga into towerdefense
cleaned up attributes package
Changed Input para of AttrManager/clean
Fixed Unit to support new attributes system/modified targetable/Added AttributeConstants class
Fixed Projectile/Changed fields in Attribute from Double to double
fix basicStateManager/cleanup
Fixed projectile/attackAction
fixed merge in attributemanager
Created framework for the Factories, and modified the classes they use
to streamline the process.
Adding actions to factory.
Added event package with Event class and Evented interface
Modified GameElement, AttackingTower classes and some test classes to be further implemented
Implemented TargetTracker interface, modified attributes-related classes