quick_frontend, primitivus: fixes a couple of issues: - chat: notification was raising an error when you just entered the room and self.nick is None - quick_widget: deleting a widget was modifying a dict while looping on it + unselect widget when it's being deleted

# TODO: remove this when RSM and MAM are in wokkel
import wokkel
from sat.tmp.wokkel import delay as tmp_delay, pubsub as tmp_pubsub, rsm as tmp_rsm, mam as tmp_mam
wokkel.delay = tmp_delay
wokkel.pubsub = tmp_pubsub
wokkel.rsm = tmp_rsm
wokkel.mam = tmp_mam