plugin events: invitations improvments + personal list - added invitation by <message> mechanism - added a personal list in PEP which keep events created by user, or in which she has been invited - new bridge methods: eventsList, and eventInviteByEmail. eventInvite is now used to invite a entity by jid (not email like before) - on invite, an invitation message is send to invitee's jid - when an invitation message is received, event is automatically linked in personal list - when creating a new event, event is automatically linked in personal list