plugin events: separation of event node and invitees node - event node is handling the main metadata of the event, and invitees node handle the invitations/invitees answers - invitees and blog node are automatically created and associated to the event, except if they are specified (in which cas the existing one are used and attached to the event node) - extra metadata are added to <meta> elements

# FIXME: remove this when RSM and MAM are in wokkel
# XXX: the Monkey Patch is here and not in src/__init__ to avoir issues with pyjamas compilation
import wokkel
from sat.tmp.wokkel import pubsub as tmp_pubsub, rsm as tmp_rsm, mam as tmp_mam
wokkel.pubsub = tmp_pubsub
wokkel.rsm = tmp_rsm
wokkel.mam = tmp_mam