Cycle DOM elementify() helper

This was inspired by a customElementify('foo-bar', Component) idea which would register a Web Component custom element 'foo-bar' which internally runs the Cycle.js app Component, so we could use this custom element in VNodes like h('foo-bar', {attrs: ...}).

But instead of using custom elements at all, I just made a proof-of-concept elementify(Component) function which just returns a hyperscript function that you can use.

Here is the proof of concept: https://github.com/staltz/elementify

At the time of writing, that example repo works, all except for the item remove event.

Reporting this here for discussion, experimentation, before putting it in the actual DOM package.