GameListAdapter is now an ArrayAdapter instead of a CursorAdapter, to allow easy sorting using Comparators. Also refactor GameListAdapter out of LibraryActivity, and make AddGamesAdapter derive from it.
Sort library by latest games first. This means that unreleased games in the far
future will be on top -- this should be changed later.
Use Cursor#getColumnIndex() instead of Cursor#getColumnIndexOrThrow() when
constructing Game objects, to improve performance (suggested by Android docs).