Duplicate sprites in 'check_for_collision_with_list'

[pvcraven]

If spatial hashing is turned on, sprites that span cell boundaries appear in the list more than once.

Use the classic 'sprite_collect_coins' example. Now you usually get a score greater than 50 even though there are only 50 coins. Some coins are double-counted.

[pvcraven]

Fixed in some prior version, I forget which.