Add damage and force falloff to shotgun, machinegun, rifle, vaporizer, okmachinegun and okshotgun

closes #2625 (closed)

^ 5/5 weapons + vaporizer have added damage and force falloff cvars now

Edited fireBullet function to accept new parameters, functions which call the old fireBullet or fireBullet_antilag should have falloff not apply.

Also edited shotgun's primary attack function to ask for falloff cvars since it's not used outside of shotgun and okshotgun's files and they both use the same function in shotgun's files.