* Never automagically acknowledge message, the UI should do this
* Add API to acknowledge a single or a list of EmpathyMessage
* Add API to get the list of pending messages
* Add API to explicitly close the underlying channel
* Ignore events from a channel that is being closed. Important events will be
  emitted when the text channel respawns.

In the future we might want to make the closing of the channel async and have
it emit signals untill closed. Mostly for the benefit of the logger. Needs some
work in the UI bits to disconnect all signals properly when closing the window
though.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>

svn path=/trunk/; revision=2128