More variety for memory-games

[hajo4]

When playing Memory-16 with cardset Matching or Matching-XL a few times,
it is easy to see that only the first images of the cardset are used.

This could be improved a bit, with no changes to the game, and no extra data,
by changing the numbering of the cards in one cardset, say Matching-XL

Here is a batchfile that just reverses the cardnumbering:
swapcards.zip

With that change, you get an almost-completely-new cardset
when switching between Matching and Matching-XL :)

[joeraz]

My plan always was to add an option to randomize the chosen cards for Matching games.

The challenge is that Matching cardsets can have a variable number of cards, which might cause issues when saving/loading games or switching cardsets.