revng ptml
This Oython tool will be used to easily work with PTML. It currently features two subcommands: * `cat` prints a PTML to the terminal, with color formatting if possible; * `strip` will strip a file of the PTML markup;
Now `revng.cli` houses the core command-line driver while the individual commands have been moved to `revng.cli._commands` and are dynamically loaded.