Support document.registerElement().

[treshugart]

Underneath the hood, skate should use the native DOM methods for registering custom elements if they are supported, otherwise just fallback to normal operation.

It should use native when:

1. Native is supported, otherwise fallback.
2. The tag name has a dash in it, otherwise fallback.
3. The component is compatible with tag bindings. If it supports other bindings then use native for the custom element and fallback for the others.