Do not check account availability at each character being typed by the user but only when it's been 500ms since he has not typed anything in.

- Handle XML-RPC request returning a string response
- Allow creating a request adding the arguments one at a time (useful for
  automatically generated wrappers where variable args functions can be an
  issue)

Negotiate RPSI as positive feedback that is the way we are using it in Linphone, keeping compatibility with older versions of Linphone.

update ortp and ms2 to fix problem when sending RFC2833 dtmfs with a number which is not the one choosen by the remote.

rewrite ugly code

That notifies the window manager to keep these windows over the main window