Printable Key Rings (Q38814)

This is a cleanup of the scad file for Catarina's makerbot keyrings. I was thinking about using part of this in another project, but when I opened the file I found that it had 13765 elements and wouldn't render in OpenCGS due to the use of some inefficient library modules. Also, the cutouts were not stretched past the faces of the parts they were cutting, causing bad rendering and possible manifold problems. I rebuilt it in 2D, then extruded to the original thickness. This also made it easy to make a 2D DXF for lasercutting.