bugfix : when a server become unavailable, self.connexions's size changed during process. Now it changes after process.

plugin.connected[account] is a number between 0 and 5 :
  0 offline, 1 online, 2 away, 3 xa, 4 dnd, 5 invisible

so when pressing control+C, exit immediatly

bugfix : when we remove an account that was online, we recieve the status "offline" after the account is removed

set error message as status message (a new status like 'error' is maybe needed to  set another icon to such contacts)