Raspberry Pi B+ cover with mounting lugs

This is a remix of http://www.thingiverse.com/thing:396917.
I wanted the ability to mount the cover using M3 bolts, so I added mounting lugs. I also wanted to improve ventilation, so I added hex formed ventilation holes in the cover.
Please note that the cover is made without any tolerances, which makes it necessary to print it with good control. Some post-processing is necessary to make the halves fit together. The end result is however well worth the effort.
I have mounted the cover belo