Added code to load a python module based on the type specified in the asset file.
New system to 'run' the extension.

Instead of switching directories the function is given an input
directory and an output directory.
Added two empty extensions and an implementation of the static type.
Cleaned up and clarified the gen.py script.

It now has more comments, better variable names and more expected
path values.
A more advanced static action type.

It now can only copy files specified with an input array in the json
rather than the whole process being an all or nothing deal.