Change the tab bar title
Add class methods to the GameResults class for returning all the game results sorted by date, duration and score
Add action methods (stubs) for the sort buttons
Add property to the GameResultsViewController that holds how to sort the results

Used an enum for its type.
Add setter for the sortType property that checks its values
Do better value checking for the sortType property setter

Add an end item to the enumeration that will specify the length of the enum.
Implement the action methods for the sort buttons
Update the updateUI method to use the sortType property to show the results sorted
Implement the allGameResultsSortedBy methods
Remove problematic keystroke
Implement the comparison methods used as selectors for sorting the array
Call updateUI when touching the sort buttons
Optimize the allGamesResultsSortedBy methods