DomView#subviews() List should update after #artifact()

[issa-tseng]

right now if you do domview.subviews() before you call artifact() you get an empty List back.

but then if you call .artifact() later, that list does not update with the new subviews.

[issa-tseng]

one possible solution is to refactor binding generation to be based on a Managed Varying.

this change would also allow wireEvents to not force artifact, but instead autowire once the artifact actually does exist.

[issa-tseng]

(same problem with stdlib listview right now)