Add ons for M5 phalanx

These are (I hope) helpful add ons to OddWorks' M5 phalanx pistol from Mass Effect. When I made my print of OddWorks M5 phalanx, I had two issues come up. First, the structures at the top rear behind the magazine came off from the rest of the left and right assemblies into several pieces and were hard to put back together. I ended printing these parts again after separating them out from the rest of the assembly. Figured I might as well make them one piece instead of having to glue the side