Added two minimap-only tiles

I'm pretty sure this is as simple as it seems to be, but I'd love double-checking.  I've tested it using data uploaded to Concordia in https://github.com/makrohn/concordia/commit/170a62dd2d90b1ee2873c23956d06ed7547a4976

Possible implementation of the expanded Collision tileset as posited in #720 https://raw.github.com/makrohn/concordia/170a62dd2d90b1ee2873c23956d06ed7547a4976/tiled/masters/tiled_collision.png