Add shoping list item prototype
Added the following model objects:item, category and shopping list.
Merge branch 'master' into bogdan
Changed deployment target to 4.3
Added DALManager class to project.
Added log macros.
Add missing xcodeproject file
Resolve conflict after merge with bogdan
Category picker added and refactorization
Refactoring of  category picker.
Merge bogdi branch.
Add categories and items property in Model class.
Add MainScreenViewController and MainScreenView classes.
Comment some logs from model classes.
Add banner view to main screen.
Add background image for MainScreen.
Add scroll view to MainScreenView.
Add page control to MainScreenView.
Add ShoppingListView and ShoppingListViewController classes.
Move ADBannerView from MainScreenViewController to MainScreenView.
Implement delegate for scroll view in MainScreenView.
Implement scrollTo functionality for page control in MainScreenView.
Add ShoppingListViewHeader class.
Add footer image view for ShoopingListView.
Set orientation to portrait only.