Multiple infinite croutons in demo do not respond to touch

When multiple Infinite Croutons are shown in the demo, they no longer respond to touch after the first one is closed.

The demo does not keep track of more than just the most recent one.

I have added a list of previous infinite croutons, so that they can all be closed.

It is a very small change, but I think the demo should be as good as possible, to convince more people to use it.