Motor mount remix

Just a modified motor mount for the tricopter. I made a few changes after I tried to assemble the original mount. Firstly I found the mounting holes way too tight for M3 screws, the 16mm distance fits my brotherhobby R6 2205 motor perfectly but the holes closer to the arm were too close to the tilt mechanism and didn't leave enough space for the screwhead. Secondly the arm for the servo link was way too weak and would break every time I tried assembling it, so I made a thicker arm. Thirdly the holes for the tilt mechanism were not the same diameter so I made it so. Also I made the entire mount a bit thicker since the screws were almost touching the stator of my motor.