upgrade the xlsforms to xform parser

[dalekunce]

potentially use or upgrade xform parser with the official one from ODK.

https://github.com/uw-ictd/pyxform
https://github.com/XLSForm/pyxform

cc @hallahan thoughts?

[hallahan]

Looks like they merged in the OSM media type, so it should be good.