8 - Proper handling of "If:" headers, WebDAV RFC 2518, 9.4.2
10 If: <http://www.foo.bar/resource1> (<locktoken:a-write-lock-token>
11 [W/"A weak ETag"]) (["strong ETag"])
12 <http://www.bar.bar/random>(["another strong ETag"])
16 <URL> (lock [etag]) ([etag2])
18 a url embedded in <>, then a set of () surrounded options which contain
19 some XML and optionally an etag.
21 Eg this is submitted by Cadaver for locking requests.
23 - reverse mapping of keys->DAV names
24 - schema queries (propnames) (partly done)
25 - queries on all attributes (propget) (partly done)
27 - SUBSCRIBE/UNSUBSCRIBE (partly done in the meantime)
28 - subscription manager
29 - httpu:// implementation for WOHTTPConnection