COIN UPDATE

-Removes the unused/dumb access stuff from space cash.
-Fixes a bug where dice would vanish if you used a hand labeller on them.
-Moves space cash/coins/mint sprites into their own file, economy.dmi. Moves mineral sheets into mining.dmi.
-Coins are flippable! Features unique flipping sprites and sound effects, and two-headed coins.

-Oh and better sprites for wooden closets too.