TileEffects and Player Items

Making first item, which places down cold tiles that freeze enemy
When player first uses item, makes new TileEffect which is added to a
list in GameManager, but is not yet made active until enough tiles are
covered. In this state, the tileeffect will be drawn as red squares to
show where the tiles will go. After the max number of tiles for the item
is place, the tileeffect will be set active, and drawn properly.