[connection] move the commit method on Connection object One step closer of standalone Connection!

[connection] move the rollback method on Connection object One step closer of standalon Connection.

[connection] pass a Connection object to RQLRewriter RQLRewriter can now directly use a Connection object. No need for specific handling session side.

[connection] Connection.execute touch Session timestamp This allow to keep Session alive while using Connection object only for database access.

[connection] Connection now call _set_user to CWUser object linked to itseld Session.user is linked to the session.

[server/session] better faking of user for InternalManager

[connection] move execute All necessary method are now available on the Connection object. So the Connection can handle RQL execution itself.

[connection] mark Connection as "not a request" The ORM use this information. Having a wrong value will lead to crash.

[server/session] ensure appobject obtained from the session are linked to the session

[connection] have rql_rewriter accession on Connection Code expecting a session search the RQLRewriter on this attribute.

[connection] move local_perm_cache management on Connection It belongs here anyway.

[session] use a rich object for timestamp This allows the Transaction to keep a reference to it

[migraction] do not access session.data directly use set_shared_data and get_shared_data instead

[connection] move relation management method

[connection] give access to shared data method A reference to session data are kept