Add new responsive algorithm

[razzeee]

Actually take up 100% of the window width - ignore, height, as we're calculating the width here.

Might fix #149

[Josh-Cena]

It may be a bad idea to hardcode the width in general, because as the issue said, this made the container unstylable. I'm also not a fan of two options that only differ in a magic constant. Maybe we can defer the width calculation to CSS, and then here use something like getClientBoundingBox to retrieve the dimensions instead?

[razzeee]

I'm also not a fan of another variant, but it's the only way to do this without breaking api.

I couldn't get a bounding rect approach to work like I wanted.

[razzeee]

Can we improve this somehow?

[Josh-Cena]

IMO, responsive is just a nice default, and if you want something more customizable you can already just pass a number in pixels to size and you can implement your own logic for calculating the right size. The only new size option I'm personally wanting to see is making the size relative to the parent container rather than the window.

[razzeee]

That would be helpful I guess. The idea with size as number is good, but it would be much easier, for my usecase, if I could set the height and the width would be automatically calculated.