Clean up and add doc script

This release is mainly a clean up, but it does have a couple substantive changes:

1. The fetch-all command is removed and "subsumed" into the fetch command. fetch-all was written at a time when the developer's Python skills were worse than they presently are.
2. The push-all command was removed. This was always a scary command that mainly existed to push tags on all repos. Once that functionality went to mepo tag push, this is now cause issues if you pushed when not desired. So, instead, users need to use mepo push on specific repos.

Beyond this, the main addition is a script that aids in making the Mepo Commands wiki page. For Markdown reasons, some of the Argparse parsers had to be changed to better work with Markdown syntax.