Add an option to generate a py-builtin.js file.
Add an option to generate a py-builtin.js file.

This is still a work in progress. Generating the file in the input directory is probably not sensible. Additionally, the path to the file is hard-coded and the source py-builtins are not included in the binary distribution from setup.py anyway.

chrivers/pyjaco,buchuki/pyjaco,chrivers/pyjaco,chrivers/pyjaco,buchuki/pyjaco,buchuki/pyjaco