Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  4d189877dacf3226d7e6036a34fd3b6eb3e2d6c8

(bug 38201) Added wb.Site.prototype.getGroup

Updates test plus some general overdue cleanup.

Change-Id: Iedfa02a75fd9ce634cb3e46bd42100838033b153