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