[WIP] Add a `self-update` command to update local phpmnd.phar from Github releases

• Adds a self-update command (not loaded unless running a phar). Also self-update --check (check if new version) and self-update --rollback (revert to previous version).
• Renames default phpmnd command to run (bash script edited to inject so phpmnd works exactly as-is).
• Some remapping to allow --help and --version/-V as expected.
• Updates are linked to stable Github releases (no version constraints included).
• Dependency to padraic/phar-updater added.
• PHP_CodeSniffer add to exclude list when creating a PHAR.

Noted as WIP for feedback. Having a run command - there's probably a better way to have a default command (where $_SERVER['argv'] isn't manipulated outside of symfony/console). This also omits the self-update command from --help.

Works, but may need some tidying for those two points.

I need to take a better look on this :)

Thanks for the review @povils - made some changes. Missed your comment on the text colouring if you have specific colour codes to fit in with your preferred theme.

@povils Pretty much done, but I may add a few changes towards the weekend to take advantage of a new phar-updater release expected shortly, and someone may know if the fugly argv function has a more...elegant solution.