Use of shlex.split() likely causing issues on Windows

[mih]

Used in

• run_procedure()
• Runner.run()
• AddArchiveContent
• AnnexRepo._annex_custom_command()
• AnnexRepo.copy_to()
• GitRepo._git_custom_command()
• sshrun()
• test_cmd.py

Solution candidate:
https://stackoverflow.com/questions/33560364/python-windows-parsing-command-lines-with-shlex/35900070#35900070

However, each use of split() should be investigated, because splitting for the purpose of Popen is unnecessary and would be immediately undone by it.