Use G_FireWeapon for all weapon modes, take weapon as an argument.
Remove buildableAttribute_t.turret*.

Buildable attacks are generally too varied and complex for generic config files.
Remove buildableAttribute_t.nextthink.

Setting think perdiods can have side effects and should only be done inside the think function.
Fix alien buildables firing without an overmind.
Set a per team maximum momentum of 300.
Add buildableAttributes_t.weapon for client side weapon effects. Fixes turret effects.
Merge branch 'gameplay/viech' into gameplay/testing