Add (UI) segmented control for user to specify match mode - 2 or 3 card match.
Included logic to enable match mode selection only prior to start of game (1st card selection)
Implemented logic for 2 or 3 card matching mode.
TODO:
 1) Enhance to show display result of last operation as text on screen
 2) Increase number of cards
 3) Improve UI - use images for the switch controls