Collisions work, can now collect balloons.

TBD make sounds and single frame animations for balloon and star to show collections- star gets bigger, mouth gets big, balloon gets smaller or pops or something (because star inhales it?).  Could have shreds of balloon confetti downwards.  Maybe some balloons have dog treats that fall to ground when eaten, other balloons are tied to ground by dog treats and float upwards to be collected by star?