transitions can't have settings or parameters

[underwatercolor]

This probably isn't a simple change, but seems worth noting anyway.

I think I have a decent use case for this, if there were anywhere to put data for a transition.

Maybe we could have a "playlist" of transitions, which would also fix the "all or nothing" problem we currently have with random transitions.

It may be worth noting that a transition [all of the ones we have?] could be thought of / represented as a masklike preset and/or a blend mode.