[ticket/12662] Reorganize and modernize the header navbar

https://tracker.phpbb.com/browse/PHPBB3-12662
http://area51.phpbb.com/phpBB/viewtopic.php?f=108&t=45679&start=60

![updated](https://cloud.githubusercontent.com/assets/3015760/3210923/13dcb72a-eef0-11e3-85a3-b553fad8fbda.png)

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PHPBB3-12662
Use SIMPLE or BASIC instead of CLEAN. I would expect the username_clean value from the users table with this variable name.