Inflatable walls and airlocks

Inflatable walls and doors added. When deflated, fits in backpack or briefcase. Expands to fill 1 tile. They can be punctured by sharp objects, Tajarans and sheer damage. When punctured, cannot be reinflated. Engineering starts with 4 boxes. Can also be ordered via QM.

In action: http://i.imgur.com/H9a7Yqz.png

Credit for the sprites goes to Chinsky.