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.
Merge pull request #1 from vtagle/master

Made some changes to allow for easier customization via subclassing.