Weapon on back sprites

Sprites for the laser cannon and pulse rifle, when slung over back
Rifle holding fix

Fixed the issue of rifle sprites not updating with drain.
Custom uniforms

Fixed the two custom uniforms present in our code. Yay.
Roll down jumpsuit

Engineering and atmospherics jumpsuits can now be rolled down.
Laser Rifle charge count

Laser rifle charge count upped to 20. Enjoy.