Fixes the SecHUD for alternative jobs
Created by: ComicIronic
Rewrote the non-casting, typechecking, utterly awful obj proc that is GetJobName(). The PDA version now returns the ID version, and the ID version now checks to see if the rank has an icon when the assignment doesn't.
This means that alternative job titles with no job icon default to the base job's icon. Fixes #1999