Validation schemas for pycadf

The TC recently objected to the apparent complexity of the model objects in PyCADF. For example: https://github.com/openstack/pycadf/blob/5792c7a1f12c885292359dc2aae11e7afc2fad38/pycadf/geolocation.py This is a lot of code to validate 7 attributes in a dict as nothing more than strings. All of the boilerplate ca...