Bottom w/corner brackets for 20mm V-slot - RRD Graphic LCD controller

This is an remixed bottom to wersy's excellent case for the RepRapDiscount Full Graphic Smart LCD Controller: [http://www.thingiverse.com/thing:87250] (I liked the original mounting on my MakerFarm Pegasus 12", but I didn't like the lasercut wood).

I was using a compatible bracket to mount it on the top of the frame, but after bumping it one too many times, decided to find a way to mount it back in its original location. I added two tabs so that it can be mounted in the corner. The tabs sh