Fixing typeerror on api creation

This module was throwing a "Typeerror: Object is not a function" when it was being created on index.js. I wasn't sure what was changed, but it seemed to be caused by how Structr was creating the object.

I Refactored it a bit and removed the dependency on Structr, while still keeping the way it (awesomely :P) lazily loaded the supervisor method calls through to the xmlrpc module.

It now works exactly as demonstrated in the docs, and is being actively used in a node app which we'll be publishing shortly.