Massive CTF updates

however, I can force players to drop the flag upon entering a vehicle

g_vehicles_allow_flagcarry have been around for quite some time, i coded that just in case someone would want a serv that disallow flags in vehicles.
if there's enough demand i can add support for not being able to enter at all.

Sure, all I need is a mutator hook function--- i.e. then I can just return true or false whether or not to allow entrance -- maybe this is a better way to handle things than forcing the player to drop the flag without warning?