Warning when performing an action which will break enableWhen logic

[mgunnerud]

When performing an action which will break the enableWhen behavior of a form, the user should be warned and guided to the enableWhens which broke as a result. The following "destructive" actions should be handled:

• Deleting an item which is the "question" condition for enableWhen.
• Moving an item which is the "question" condition for enableWhen down in the questionnaire hierarchy so the enableWhen dependent on the moved item is shown above the moved item in questionnaire.
• Changing the type of an item which will invalidate the answer[x] property of enableWhen.