- new Pubsub invitation plugin, to have a generic way to manage invitation on Pubsub based
features
- `invitePreflight` and `onInvitationPreflight` method can be implemented to customise
invitation for a namespace
- refactored events invitations to use the new plugin
- a Pubsub invitation can now be for a whole node instead of a specific item
- if invitation is for a node, a namespace can be specified to indicate what this node is
about. It is then added in `extra` data
- an element (domish.Element) can be added in `extra` data, it will then be added in the
invitation
- some code modernisation
795931373a