Clarify concept of host to mean dom host. Related:

[sorvell]

• remove configuration element list after configuration.
• shady dom dynamically re-renders only dirty roots.
• x-scope styling styles elements found via dom.
• make template stamped element hosted by templateInstance
• marshal templates at config time and make x-repeat render in ready.

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[sorvell]

@kevinpschaaf gave LGTM.