Broan Range hood replacement knobs

This is a set of replacement knobs for my broan range hood. They have the
advantage of being larger and easier to grip. For some reason, the old one
stripped itself out so I spent some time and made new ones in OpenSCAD.

The source is included, and there is a ifdef statement to switch back and
forth between the one for the fan and the light. Also, feel free to remix if
needed. To create all the knurling, I used aubenc's Knurled Surface Library
v2 (https://www.thingiverse.com/thing:32122). Handy little library to keep
in your design arsenal.