Add support for skins to set attributes of <html> element.

* Useful for device/profile-specific stuff (e.g., manifests)

Change-Id: I65f4d3454ae52a25fe4c6e9f2119129425b3de7a
Change location of period in img-lang-info

Per https://translatewiki.net/wiki/Thread:Support/About_MediaWiki:Img-lang-info/cy/reply_(3)

Change-Id: I81441e10083a610464380a009fa467bdd5c40cc0
Merge "Add support for skins to set attributes of <html> element."