user/jszakmeister: fix the highlighting for my markdown code blocks
Use unabbreviated :command.
:DiffOrig now closes other windows before starting diff.
Use :OneWindow with <C-W><C-O>, <C-W>o, and \sv.
Add :DiffClose command, and invoke as part of :OneWindow.
Add :Diff command.
Add missing tags files.
Merge branch 'js/mine'
Add :VisualHelp and visual-mode mappings to invoke.