core (xmpp): properly clean profile data in case of startConnection failure: - profile is now always removed from profiles_connecting - an exception is raised if client already exists only if client is connected. Otherwise, it's deleted (this allow to keep session open to e.g. modify settings in case of failure during connection)

You'll find install instructions in documentation (see doc/installation.rst).

If you need help, come the SàT official XMPP room: sat@chat.jabberfr.org or join us with a web browser via https://chat.jabberfr.org/converse.js/sat@chat.jabberfr.org