M1014 shotgun

Well its the m1014 semi auto shotgun, nothing too fancy, probably. To further differentiate semi auto shotguns from their pump action brethren, I gave them the ability to burstfire to shots in quick succession, this change applied to both the two saiga-12 guns and the m1015 (please tell me if I missed others).

I also removed the never jams tag to the saiga, brief googling points out that they can indeed jam, but I am not a gun expert.