Element.remove not supported on IE11

[machty]

There's a lot of places throughout the codebase (example) that use Element.remove(), but this isn't actually supported in IE11 (and presumably older IEs). In IE11 the chart won't render and you'll get an error about missing method remove.

I was able to fix it with this polyfill, but I'm thinking you shouldn't need something like that for keen-dataviz to work out of the box.