Cirrus updates for 1.23

This is literally just merging the master branch of Cirrus to the 1.23
release branch. Almost everything just works. What doesn't:
1. Highlighting category matches - these are ignored
2. Auxiliary text items - these are just merged into the main article text

Change-Id: I166433a75b2ef2efcbb250b4662c9506796fd0c0