GoPro mount for Sunpak 6200 tripod

Single-camera version of http://www.thingiverse.com/thing:707160. Base is designed for Sunpak 6200, may or may not work with other tripods (dimensions: bottom square 42x42 mm, top square 34x34 mm, height 8 mm.) Extra care taken to fine-tune a good fit between the clamp and the enclosure, and to add reinforcement ribs (3D-printed clamp lips are flimsy and snap off easily, especially when printed in the "natural orientation" for this mount, with layers parallel to the ground.) Go easy when tighte