fixed IVR Gateway related tests
refactored correctAnswer -> correctOption
#11: added JSON Views; modified published Course JSON appropriately to IVR API
removed db migrations
#7: Added possibility to select the quiz from treeView
#7: Corrected recursive addition/removal of nodes
#7: Fixed bug with angular scope
#11 refactored question options, fixed JSON representation for Quiz
minor fixes
fixed creating and updating chapter without quiz assigned