Updated the default template and renamed one view script

* The default template now allows the 'files' menuitem to be selectable
* The example directory.php now sets the menuitem 'files' as selected
* The view script 'system.php' is renamed to 'homepage.php' as that better describes what it is
Updated index.php to define ENT_HTML5 in case it is not defined (PHP <5.4)
Some more changes to allow editing of user and group data within the webdav namespace (instead of a seperate website)
Made all user details available as properties