Update Smsit.class.php

Better version

Is there a way to get the result error code to frontend ?
now using symfony HttpFoundation session object for managing user
session
Merge pull request #90 from nerdalertdk/patch-1

Update Smsit.class.php
Status list layout
Saving status layout mode
finishing #86 by jerome (adding sql to install, changing primary key,
..)
renaming getPreferences method to loadPreferences to indicate you are
not "get"ing anything
status.tpl.html: make sure label matches value keys
install docs: adding user-specific cron example for distros like debian