Pixel Collision

I added the Intersect Pixels  method and I changed the update method to
call the Intersect method. I added some lines off code to the ball and
platform class to make the intersect method work. Some chnages will be
needed to work with Jorenz code since all his fields are private.
Merge remote-tracking branch 'origin/Brian_Collision'

Conflicts:
	PuzzlePathDimension/Ball.cs
	PuzzlePathDimension/Game1.cs
	PuzzlePathDimension/Platform.cs
Temporary fix.