[sugar] Buddy-left working

[Morgan Collett]

Morgan Collett wrote:
> The Presence Service should now emit a working buddy-left signal when
> someone leaves a shared activity. Shared activities should also
> disappear from the mesh view when everybody has left, although I'm still
> chasing down some cases when this does not happen.
> 
> The code is still being improved, so ping me if you have any issues with
> this. (or log a trac ticket on the presence-service component if I'm not
> around...)

I had neglected to merge a patch for sugar which was also required - so
it wasn't working but is now.

Regards
Morgan