Unminify WebGLTFLoader JavaScript
Update Montage package dependency
Upgrade promise API usage

end() -> done()
Change WebGL Loader to use require instead of XHR

The model description is now loaded through the require system instead of a manual XHR.
This is necessary to make the application work after mop because the directory names might change.
A base URL is now also given, based on the package location, for the same reason.
Remove suffix ".js" from module ids

Mop isn't able to handle these an fails silently.