LMSConfig further integration

Removes global $CONFIG variables.
Changes access to config variables from $CONFIG['section']['variable'] to LMSConfig::getConf('section.variable').
Changes parameters of $LMS->SendMail() and $LMS->SendSMS() (with backward compatibility).
Changes the way of getting $DB handler from geDB() to getInstance().
Changed constructors of LMS and Userpanel classes (removes $CONFIG).
Removes CONFIG properties from LMS and Userpanel classes.