Mentor permissions fixes and such.

Created a helper proc /proc/is_mentor(client) use this when determining if someone is a mentor and they aren't the usr of the proc (rights_check uses usr)

Mentors will no longer hear ghosts while playing
Mentors will no longer see orange text around names in check_player_age panel if they have special_roles
Mentors will no longer be able to tell players with special roles through the use of player_panel
Mentors will no longer be able to aghost, use antagHUD, then return to their bodies.