Miscellaneous Updates
* Removes prev_move from mobs and the Click() code, beacuse it was apparently not actually used
* Additional forbidden spawn item for sandbox panel (notably Apocalypse grenades, but also non-sane objects)
* Minor optimization for ID card access checking because I was bored
* Adds a box full of fast food, and a cargo crate with several of them.  Needs a good fast food bag sprite.
* Adds cleaning and dirtying reagent blasters, I couldn't explain why.  They are available through cargo.
* Adds the medal box to the captain's quarters
* Various fixes to floors and floorbots:
+ Floorbots will no longer chase after each other's assigned tiles, so they work better as a group
+ Floorbots will now fix broken and burned plating.  This does not cost them tiles.  Carpet, wood, and etc should also be fixed when broken.
+ Floorbot "improve tiles" now actually improves tiles
+ Floorbot "bridge mode" now lets you build bridges into deep space.  Previously, it would never build in a space /Area, even when bridging.
+ Floorbot intelligence might be a little better.
+ Carpet can now be installed properly, although there is no canonical source of carpet tiles.