VID-557 Show an error if an unauthorized user tries to view a lightbox image.
VID-557 Accidentally dropped negation
VID-557 Fixes to i18n messaging
VID-557 Don't use $wgUser when we can use $this->wg->User
Merge pull request #1086 from Wikia/VideoSprint28-VID-557-UnauthorizedUsers

Video sprint28 vid 557 unauthorized users