Merge branch 'ab/mediawiki-namespace'

The remote-helper for talking to MediaWiki has been updated to work with mediawiki namespaces. * ab/mediawiki-namespace: remote-mediawiki: show progress while fetching namespaces remote-mediawiki: process namespaces in order remote-mediawiki: support fetching from (Main) namespace remote-mediawiki: skip virtual namespaces remote-mediawiki: show known namespace choices on failure remote-mediawiki: allow fetching namespaces with spaces remote-mediawiki: add namespace support