Added some todos, ideas

To discuss
Merge remote-tracking branch 'origin/nrvnTesting' into dev
Added the filter "CanModifySurvey" in the Controller (root controller).

Now, to add this filter, we'll need to add the "CanModifySurvey" in the controller's filters and add a "filterCanModifySurvey" method.
Look at the QuestionController and the PropositionsController for examples.
Merge branch 'dev' into FireGhostTesting
whoops
Removed the "beforeDelete" method because it's in the Controller now.
Merge branch 'dev' of https://github.com/FireGhost/app_surveys into dev
Merge remote-tracking branch 'origin/dev' into nrvnTesting