Added support for CommonJS syntax for extension code
The define(function(...) { boilerplate is now no longer required and
inserted automatically (if not already present) making code feel more
like plain CommonJS code.

In addition, the configfs! prefix is no longer required if you use
relative paths, that is require("./bla") is now translated to
require("configfs!./bla") automatically. In addition, added better logging support for sandbox code (thanks @TheKiteEatingTree).