Cop and medic fixes and improvements

* added clothing update for medic (still need to redo backpack texture)
* added map marker tracking for medics
* added map marker tracking for dead medics and cops on cop map
* fixed minor cop housing issues
* added checkpoint to highway south of airport with advanced gate keeping (check the towers as cop)
* fixed shitter sound
* fixed medic heli spawns so they don't get damaged anymore.