Collection Renderer (Now a module!)

OCG is a MediaWiki service integrating with the Collection extension
to provide article bundling and rendering for offline consumption. It
provides the 'Print to PDF' sidebar functionality as well as book
creation through Special:Book.

Change-Id: I3c95af9a64a7d5830687cf3657c9afa6635a680f
Merge "Collection Renderer (Now a module!)" into production