Bug in W3C Annotea service

The Annotea spec defines the query to get replies to an annotation to be
"w3c_reply_tree".  Unfortunately, the W3C Annotea server uses
"w3c_replyTree".  This is a bug, and should be corrected in an upwards
compatible fashion.

Some Annotea clients (e.g. Annozilla) have been implemented against the
W3C Annotea server's behavior rather than the spec.  Others (e.g. the
WAINU library) implement the spec.  This means that Annotea servers need
to implement both versions of the request to support the range of
clients.  This probably should be mentioned in the Annotea spec as
"implementation advice".

-- Steve