Fall back to inline-block if flexbox is not supported

[dagda1]

How would you feel about a PR that made inline-block was a fallback rather than having to declare whether to use Flex or Grid?

[jxnblk]

Personally I'd rather keep that out of this project since inline-block and flex box behave quite differently, and I would imagine that most users wouldn't want/need to use a fallback feature. That said, I could imagine that a fallback grid component could be composed from this library (i.e. as another npm package) for people who do want it - hope that makes sense

[dagda1]

I'm working on such a component. Really liking the grid!