Airlock Painters

Proposed commit by Ricotez. http://forums.nanotrasen.com/viewtopic.php?f=16&t=12053
- Use the paint sprayer on an airlock assembly to have it change colours. Works on both solid and glass airlocks.
- I've change it to use toner as 'ammo' though, instead of having 5 uses with no way of refilling it.
- Sprites by Teh_Wolf. In-hand fixes by Cheridan