Implement ViewHolder pattern on the GameListAdapter.

An optimization to the game list screen. In the case that there are more rows than can fit on screen, when the user scrolls to make another row visible, Android recycles the pre-inflated views from the row that just scrolled off screen. This avoids inflating views every time a new game comes on screen, and should enhance performance for users with many games.

So on Android, probably not a lot of users. But it's good practice and should be done with every ListAdapter class.