Allow lists in class

[TiagoCavalcante]

In React the following pattern is pretty common:

<div className={`a b c ${d}`} />

And then I discovered SolidJS had classList, but to say the truth I got a bit disappointed when I discovered it wasn't for what I expected, and it give me an idea: why not allow a list of strings along with a single string in class?

<div class={["a b c", d]} />

[ryansolid]

This might be of interest.

ryansolid/dom-expressions#88

This PR only looks at the runtime portion and there are compiler implications. Especially when it comes to optimization. I think to support this we'd need to move towards having only a single class setting prop but I need to evaluate if the de-optimizations there to the common case are too severe and if there are ways to work around it.