Parametric Box with Rounded Corners

This is a remix of http://www.thingiverse.com/thing:71370
I thought this box was great, but was not thrilled about its squareness. I was looking for a box for my reading glasses, and this would be almost perfect.
I am new to OpenScad, so I did not come up with a good solution to make the corners round. I finally found the OpenScad library published by Randy Young , which has a RoundRect function that worked perfectly for my needs:
https://github.com/ethanrublee/capture_bot/blob/master/Libs.sc