[Ocs] add comment should return id

[Mateu Batle]

Hi all,

let's give some life to this new freedesktop list, thanks Frank for
getting it :)

The request for the new spec is when a new comment is added,
I think the response back to the client must include the new id created
for the comment.
I need this to immediately rate the comment just after creating it.

I have thought of a workaround but it is neither elegant, nor efficient
nor safe, so please let's get this.
The workaround would be get all the comments again, and check date /
title / text / user.
I think it is small requirement for the server, but a big win for the
client.

Actually I think this should be for all add / create / new operations,
not just for comments.

cheers
  Mateu