Here is a DRAFT version of a squircle node.
Add on an Output node, and the script works. Still does not like a sqfactor of 0.0.
Place the two files in the extension directory of nodeeditor.
Alternatively, the squirclefn file can be placed in the lib directory. It just contains two functions.
Still wondering if the two functions could be put in the squircle.js node file.

More testing to do...

- Brian

See post 38 for "final" version.