Updated mediawiki/extensions
Project: mediawiki/extensions/MultimediaViewer  3f9becc01b28912ad513b4d457455a18d81939d0

Add Thumbnail model

Also refactor size calculation a bit - I found target/requested
harder to remember.

Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/155
Change-Id: I4781cdd7004e9a8e36875c152e1d3a335a55b7d7