Adds PrintablePageAsOfRevision view that uses an iframe

[halfak]

No description provided.

[Ladsgroup]

I tried to test it in labels-experiment but it didn't work the way I expected: http://labels-experiment.wmflabs.org/ui/wikidatawiki/

Also the widening looks good on wikidata but I don't like this for other wikis. Can we make it configurable?

[halfak]

@Ladsgroup: Strangely, that screenshot seems to be using the old PageAsOfRevision view rather than the PrintablePageAsOfRevision. I can tell by the color of some things. However, I think you make a good point about the change to width. Let me see how that might be addressed.

[halfak]

OK i brought the width back under control. I also did a little bit of styling with the PrintablePageAsOfRevision view so that it will not cause weird scroll bars as often.