Going to next card

[jbv at mozik.fr]

Finally, I found a workaround : instead of a single stack with 2 cards,
now I have :
- 1 main stack with 1 card
- 1 sub-stack of the same size with 1 card.
And instead of "go cd 2", I use :
    hide main stack
    show substack

With only 2 cards it's ok, but in a project with many cards and lots of
controls on each card, replacing multiple cards with multiple substacks,
I'm not sure...

jbv