override BuildingControls.js and Optimized Pic

1.Adjust the size of object for Zombie, Plants, and Buildings. The
object contour could be bigger than the picture now. Therefore, the
strange red triangle will no longer exists.
2. Override method in BuildingControls.js. Barn occupies 4 tiles and
ColdStorage occupies 6 tiles for now. No longer use the setInterval. Now
the broswer will load the picture statically.
3. TODO: fix method collisionDetectForOneTile and create method
collisionDetectForFourTiles and collisionDetectForSixTiles.
4. WHEN WILL THIS APPLICATION CONNTECT TO DATABASE?!