Parametric USB microscope (or anything) mount for PVC

Yet another mount for [cheap USB microscopes](http://www.ebay.com/sch/i.html?_nkw=usb+microscope&_armrs=1&_from=&_ipg=). I didn't like the ones already posted, since they either involved a ton of printing, had very complex assembly with precise tolerances, or relied on the the scope holder that comes with it, which I found to be the most finicky part.

This design is very simple -- a coupler that grabs onto a 1" PVC shaft, with friction set by a bolt; this mates with a holder, also set by fric