QAV210/180 GoPro mount

QAV210/180 mount fitting the original Lumenier QAV210 and QAV180 - 20 degrees tilt.

This is revision 2, the first revision had the screw holes not properly lined out with the frame. The camera has also been moved 5mm to the front.

**Changelog**
* 2016-04-21: Rev 3 - added support for the backside of the mount. It broke off after a few crashes.
* 2016-03-31: Printed and verified, fits perfectly. Uploaded some photos.