added eventlog

the eventlog is now avalible for all users, it should be a check so it's
only avalible for superusers
Merge remote-tracking branch 'origin/duggasys-Quiz' into duggasys-feature-eventlog

Conflicts:
	DuggaSys/header/content/header.php
change url to eventlog
Changed the wording on the login failure entry

Clarified that it's a username someone tried to log in with, not an
error for an actual user.
The block needs to be closed

Or things might blow up on us.
Made it possible to define severity levels

Event type in the database has been changed to an int to allow filtering
on severity. Added support to the eventlog page for filtering on this.
Updated the headers in eventlog.php

This should make more sense to users of the system.
Make the dropdown only change if data exists

Selecting an empty value leads to silly results.
Merge branch 'duggasys-Quiz' into duggasys-feature-eventlog
Merge remote-tracking branch 'origin/duggasys-feature-eventlog' into duggasys-Quiz