Issue #406 - prevent user to save survey without title
Issue #405 - prevent user to go to notifications when survey not saved

* in addition, we check if questions are available before going to translations
Issue #409 - correct text tooltip permission levels
Issue #410 - correct spelling mistake

* a new issue #421 was opened because the text actually refers
to functionality that is not used at this moment.
Issue #413 - make assignment name and dates mandatory fields
Issue #415 - minor fixes in alt text