fix code quality. if user presses Cancel in Status change dialog do not set the new status; add comments to code, make it cleaner (use 'SEPARATOR' and not '' for string for combobox; HIG (add ... to finish menuitems that need it and add a missing mnemonic)

use better image for rename/changing status (generally means: you have to type new string). thanks  Bernhard Walle

TODO:
global status combobox need it

catch a typeerror tb and fallback, because vanilla gnomepython 2.12 has bad patch in Mandriva. thx dakilla

now on focus out and on tab switch groupchat window adds seperator to point where we where when we force losing focus in the conversation. TODO: position it better, add tooltip what ------ is