Minor update 0.1.3b (hotfix)

Uh-oh, it looks like I've unleashed quite a few beasts with the previous update... This hotfix update is there to fix that!

• Optimized crate logic code.
• Bugfixes:
  • Out-of-bounds on level 3 fixed.
  • It's no longer possible to "fuse" crates by pushing them to the same crate-in-hole tile.
  • No longer possible to "fuse" crates by pushing them to the same button tile.
  • And no longer possible to "fuse" crates by pushing them the same opened-gate tile.

By the way, 0.1.4 is coming soon with A LOT of new levels, so stay tuned. ;)