moving loggedinuser => loggedinusername in includes and Auth.pm :

moving loggedinuser => loggedinusername in includes and Auth.pm :

The $loggedinuser in Koha is the CODE of the logged user (result of get_user_and_template subroutine).
BTW, in get_user_and_template subroutine, the TMPL_VAR loggedinuser is replaced by the NAME of the user.
This is troubleshooting.
so, I replace the name by the "loggedinusername" template variable.
If you want to add the username somewhere, just add <TMPL_VAR name="loggedinusername"> in the template.

Fixes bug #401