* fixed a bug when we remove a contact from our contact list (before we did not remove contact from roster_group table)

* now there is no more sparkling when we update the RosterWindow with the roster received from the server (when server does not handle roster versioning or when it resends the whole roster)

* In order to allow the viewing of the roster when we are offline (and some other cool stuffs), with and without roster versioning, now we load roster when RosterWindow is created (at gajim startup). Fixes #3190

* in order to permit roster loading at gajim startup we need to save all roster pushs (even if it's not for versioning)

* fixed a bug (when a contact does not have a name)

* now we load roster from DB when we receive an iq result for the roster without any query
* added a "force" argument to NonBlockingRoster.getRoster(), to force the return of the instance

* we now handle roster push and roster reception
* changed version number in src/common/defs.py

* added "roster_version" in configuration to save roster version for the account
* added "ver" attribute when gajim requests the roster

prevent traceback when we click on Rename in accounts window, but no account is selected. Fixes #5019

Add a second timeout to differenciate keepalive and ping alive packets. We now wait 55s before sending a keepalive (whitespace packet) and 2 minutes before sendind a xmpp ping (and then we wait for 1min the answer before reconnecting) Fixes #4643