code formatting
More strict input handling
Merge remote-tracking branch 'origin/master' into 1.4.5

Conflicts:
	zp-core/functions-basic.php

	modified:   zp-core/admin-functions.php
	modified:   zp-core/admin-tags.php
	modified:   zp-core/admin-users.php
	modified:   zp-core/functions-basic.php
	modified:   zp-core/functions-i18n.php
	modified:   zp-core/lib-auth.php
	modified:   zp-core/zp-extensions/user_groups/user_groups-tab.php