Move faction attrib into BattleObject base class
Change renderBattleObject() to draw square instead of circle symbol
Add Factory class
Merge branch 'feature/battle_objects' into feature/unit_creation

Conflicts:
	Overload/src/com/spillovergames/overload/BattleObject.java
	Overload/src/com/spillovergames/overload/BattleView.java
	Overload/src/com/spillovergames/overload/Defaults.java
	Overload/src/com/spillovergames/overload/Droid.java
Remove debug logging
Add addObject()
Refine buildUnit()
Enable player on-demand unit creation
Fix unit size to use radial size consistently
Add color to unit symbols
Centralize map logic into BattleMap class