RADIO SPRITES UPDATE

-New sprites for about half of the headsets:
-Cargo headset now tan instead of white, science now has a unique headset instead of using the command headset sprite (wtf?), medical headset center changed to green from blue. New sprite for medsci headsets.
-Command, centcomm, & basic headsets tweaked a bit, with better shading.

-Made descriptions for command headsets less bad.

Fixes #568