Displaying player shadows with cg_marks 0 and not applying r_picmip to them

[Irbyz]

Currently shadows from player models (cg_shadows 1-3) are not displayed unless cg_marks is to 1.
I heard this was done in AfterShock because people could gain an unfair advantage by using shadows, but I don't know exactly how? And since shadows still can be enabled with cg_marks 1 this seems especially dubious.

Also with high r_picmip values shadows will be displayed as gray squares.
I'm not sure whether there should be a new bit for cg_nomip to not apply r_picmip to shadows or it should be just always not applied to shadows.