Weapon firing action should be groupable

[rikus]

On ships with multiple weapons, they should be able to fire in groups. There should be a dialog for configuring weapon groups, and also one for moving weapons to different slots on the ship itself. All of this pretty much depends on the completion of ticket #107.

Example group configuration:

primary

forward Strong Laser
forward Plasma Cannon
center Strong Laser Turret
forward Torpedo Launcher

secondary

rear Plasma Turret
rear Torpedo Launcher