[repo] on repository shutdown, we've to close the new eid creation connection

[auto-reload] we should never call load_module with use_sys=False, that may lead to inconsistency with module interdependancy (eg module get imported by another one, then is reimported by the vreg to load its appobjects. Cleanup of sys.modules done before reloading should be enough.

[rset] do not filter rsets with __getstate__, ensure whatever flies with pyro has no .req attribute, also set the ._rqlst to None since it will be reconstructed later on demand

[security] SchemaRelation.has_perm grows to new arguments allowing to specify subject/object entity type when actual eid are not known, but their types are

[linkto action] refactor to ease overriding to control redirection

[hooks] entity_oldnewvalue should never return _MARKER: if the attribute isn't in the entity dict (hence unmodified), return the old value