Fixed issue #154; Dynatree (tree panel) een verder openklappen

Also added sorting of the directory listing
Clean up of view/beehub_directory.php

* Indenting should now be correct (and with spaces instead of tabs)
* Almost HTML 5 compliant (only need to substitute the 'name' attributes)
* Removed some old, out-commented code
* Rewrote small parts for clearity