Try to set namespace
Certain buggy clients (Flycode) expect DAV: namespace hardcoded to "D:".
Moreover, Flycode expects all props to always be prefixed.

* This is Flycode does a string match for ":my_property", *assuming*
  (although ignoring the actual value) that the property element
  always has a namespace prefix.
Don't include the full URI in the collection entry for ".".

* This was causing some clients to not manage to infer that the
  "." entry was itself and should not be nested.