Merge branch 'ab/mediawiki-fixes'

Modernization and fixes to MediaWiki remote backend. * ab/mediawiki-fixes: remote-mediawiki: use "sh" to eliminate unquoted commands remote-mediawiki: annotate unquoted uses of run_git() remote-mediawiki: convert to quoted run_git() invocation remote-mediawiki: provide a list form of run_git() remote-mediawiki tests: annotate failing tests remote-mediawiki: fix duplicate revisions being imported remote-mediawiki tests: use CLI installer remote-mediawiki tests: use inline PerlIO for readability remote-mediawiki tests: replace deprecated Perl construct remote-mediawiki tests: use a more idiomatic dispatch table remote-mediawiki tests: use "$dir/" instead of "$dir." remote-mediawiki tests: change `[]` to `test` remote-mediawiki tests: use test_cmp in tests remote-mediawiki tests: use a 10 character password remote-mediawiki tests: use the login/password variables remote-mediawiki doc: don't hardcode Debian PHP versions remote-mediawiki doc: link to MediaWiki's current version remote-mediawiki doc: correct link to GitHub project