When DAV-aware nodes want to return properties, they might need to
have xml attributes or single instances of sub-elements.
Example:
return ('aprop', 'D:', ('foo', 'D:', None, { 'name': 'bar'}))
will result in xml:
<D:prop>
<D:aprop><D:foo name="bar"/></D:aprop>
</D:prop>
bzr revid: p_christ@hol.gr-20101012104029-gq6hhjki4i52n8qh