Fixed error with get method in nodemap to not return null
Merge pull request #50 from Tadimsky/buttonActions

Button actions
Made map start painting itself
Got some better painting order
Made Resources and Terrain be observed correctly
Changed color of background. Spent more time trying to figure out painting order
Got painting of nodes to work correctly
Merge branch 'master' of https://github.com/Tadimsky/vooga into map-painting

Conflicts:
	src/vooga/rts/state/GameState.java
Merge pull request #51 from Tadimsky/map-painting

The map is now able to paint itself correctly by the depth. The map also observes units, terrain and resources.
refactoring gamemenus into submenus
spliced the gamemenu into three separate components
Button now only handles singular buttons (no menus buttons)
ActionButton is a reflection of the ImageButton class, used by ActionsSubMenu
Refactored code to make game menu distinct, paintable partitions
updated observer pattern