initial commit
added main storyboard with navigation controller
added logo image and buttons to main menu view
added constants file
added rating view for quiz cell
added quiz cell view
added quiz and question to model
added quiz and question classes
added abstract select controller
added abstract menu class
added category images
added quiz cell images
fix category images
fixed rating view class
added init with server API to quiz
added background color
added default select behavior
added download controller
added download scene