Case Bottom for RAMPS 1.4 - No Clamps!

Summary This is a modifications of http://www.thingiverse.com/thing:32737 but I have removed the clamps or tabs on the edge of the base panel. I added four screw pilot holes if someone needs to mount it on a flat panel like I need to do. Just checked the first printed version, and the holes are in the wrong places. They contact the Arduino if they are not recessed just right! New version now corrects that....