Declared the UICollectionViewDataSource and UICollectionViewDelegate protocols so subclasses can override those methods.
Moved the init code in initWithFrame to a separate function so that initWithCoder can call it as well so setting up a MNCalendarView object in InterfaceBuilder works as expected.
Created a method for registering the classes used for the UICollectiveView so that when the class to use for cells are changed, it will get picked up on by the UICollectionView.