Changed block collision, Added block destruction

Changed BlockCollision class to handle the change of block sprite
according to hit count.
Added BlockDestruction class which is actually the old BlockCollision
object. It is now called inside the collision if the hit count is high
enough and a destruction sequence is needed.
Moved Tiled files, Recreated levels

Moved Tiled files out of the assets folder and into a folder titled
TiledFiles so it doesn’t get bundled into our application.

Recreated levels in a smaller format so it takes less time to finish
them.
Merge branch 'Block-Health'