newPage and selectedArtboard missing.
At the time of writing I can't seem to locate any hints of the signature `newPage()` within the context of a `Document`.

I'm hopeful that selectedDocument.newPage() is a likely outcome here.  Currently I've had to revert to older methods to achieve this (`context.document.addBlankPage()`) then either find it by name or set it to being selected. So far i've been able to route back into the API layer but its quite cumbersome to retain this parity.

Also in the same line of thinking, given there is `selectedPage`, `selectedDocument` why is `selectedArtboard` not appearing (is that in the backlog or something?).
