BIND issue: 3.1-clarify-resource-id

(see 
<http://www.webdav.org/bind/draft-ietf-webdav-bind-latest.html#rfc.issue.3.1-clarify-resource-id>)

This one came up when Yaron asked for a way to create a new binding 
without risking a race condition (where the URI given in the <href> 
element is re-mapped to a different resource in the meantime).

Turns out that BIND does not require the <href> to use an HTTP URI -- so 
it would be possible to use the value of the DAV:resource-id instead, 
such as in

BIND /CollY HTTP/1.1
Host: www.example.com
Content-Type: application/xml; charset="utf-8"
Content-Length: xxx

<?xml version="1.0" encoding="utf-8" ?>
<D:bind xmlns:D="DAV:">
    <D:segment>bar.html</D:segment>
    <D:href>urn:uuid:6ed638d6-908d-11dc-9f44-0015c5140153</D:href>
</D:bind>

Of course that may not be possible with all servers (basically it 
requires the server to be able to internally *resolve* the resource-id).

This may not been clear previously, so the proposal is to add the 
following note to the definition of DAV:resource-id:

"Note: by definition, the URI specified in the DAV:resource-id property 
always is an alternate URI for that resource."

BR, Julian