plugin invitation: pubsub invitations: - 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

include MANIFEST.in sat/VERSION
global-include *.py
global-include *.ini
global-include *.po *.mo
global-include CHANGELOG COPYING* INSTALL README*
global-include *.sh
global-include *.yml *.yaml
global-include Makefile *.rst *.bat
graft misc
graft doc
include sat_frontends/jp/jp sat_frontends/primitivus/primitivus
include sat/bridge/bridge_constructor
global-exclude *.un~
prune sat/bridge/bridge_constructor/generated