remove Scroll on Chrome browser
changed save-message in treeview; fixed saving quiz; added version; refactores 'lessons' name
Merge pull request #5 from pmuchowski/phase2

remove Scroll on Chrome browser
Node children are now populated on addition
Added null checking to switchUnitState
Changed isChildren to check node id instead of its name
Changed lessons property to message in TreeView
Limited number of questions field in quizzes
Add Location setting on Courses Tab