GoPro Session Superview Case for Modular Multicopter Mounts

I remixed [mr2fpvninjas](http://www.thingiverse.com/mr2fpvninjas/about)'s fantastic [THE Gopro Session Superview cover for FPV quadcopters etc](http://www.thingiverse.com/thing:1791443) with the following changes:

- Added tabs for a 20mm battery strap for use on modular mounts
- Tabs include hard coded printing support since I couldn't get Cura to cooperate
- Made the hole in the back bigger and added a cutout so the Session's back button is accessible

I use it on my [x210 V+ GoPro Session Mount](http://www.thingiverse.com/thing:2182766).

#### 2017.04.15 Update
- I noticed a tiny bit of the case in superview recordings. I've trimmed a bit from [mr2fpvninjas's version 3.7 case](http://www.thingiverse.com/thing:1791443) to eliminate the offending corners.

#### 2017.04.29 Update
- A particularly nasty encounter with a chain link fence revealed weaknesses in the battery strap tabs. They are now 2mm wider and 1mm thicker.