Spawner GUI 1.1

Adds a GUI to all mob spawners, that will allow you to pick what mob to
spawn. I also reallowed mining spawners. You can disable spawners with
redstone aswell. Should be compatible with all mobs, but don't expect
the mobs with special spawn conditions to work everywhere. Animals
require grass, Monsters require darkness, Slimes require being in their
special chunks, and 0-16 depth. Requires ModLoader 1.1.