tmp
Rewrote OuterWall to work the same way as InnerWall. Uses a function to create all 4 walls.
Cleaned up Obstacle model (is it a model..?)
Moved the positions of the inner walls to be more centred. Created all the walls, and looped through to add them.
Cleaned up outerWall loop
Merge branch 'inner-walls'

Conflicts:
	main.lua
Fixed up tests, and got working boundaries
Fixed bug, was reading left by default every time..
Added variable for screen size
Fix code layout in outerwall spec