Vive Tracker Limb Mount (Improved)

A modified version of Chris Larkin's limb mount (https://www.thingiverse.com/thing:3280609).

I changed a few things to better suit my own supplies:

- Widened the holes to 21x4mm so they can comfortably fit 20mm wide velcro straps
- Have the little orientation knob as a 3d printed protrusion, because I didn't have any bolts that fit
- Added holes to the side of the strap holes, so that it is easier to pull them through (e.g. with tweezers)
- Increased the thickness of the plastic between the tracker and where the screw sits by 1mm, because my 1/4 screws were too long and required washers