Some fixes for category sorting
German update
Dutch update
Remove variable as it is no longer used.
Merge remote-tracking branch 'upstream/master' into upstream

Conflicts:
	zp-core/admin-functions.php
	zp-core/locale/de_DE/LC_MESSAGES/zenphoto.mo
	zp-core/locale/de_DE/LC_MESSAGES/zenphoto.po
	zp-core/locale/nl_NL/LC_MESSAGES/zenphoto.mo
	zp-core/locale/nl_NL/LC_MESSAGES/zenphoto.po
	zp-core/zp-extensions/zenpage/admin-functions.php