quick frontend (chat), primitivus(chat): properly clear occupants on resync: occupants widgets were not cleared in Primitivus on resync while occupants dictionary was, resulting in nicknames sometimes apearing doubled in Primitivus MUC rooms. A new occupantsClear method has been added in QuickChat, so it can be overriden by frontends to clear widgets or other representations of occupants. fix 304

# XXX: the Monkey Patch is here and not in src/__init__ to avoir issues with pyjamas compilation
# TODO: remove this when changes are merged in Wokkel
from sat_tmp.wokkel import install
install()