Add a Python command-line interface

[Kodiologist]

Description

• Closes Add a Python command-line interface #440

How Has This Been Tested

So far, just by trying it. If you like it, I can add real tests to this PR.

Unrelated, but I noticed that the syntax in the documentation doesn't match what is actually tested for rerolling (documented as 1d20r#1, implemented as 1d20r==1) and macro calls (documented as #PLANETS, implemented as @PLANETS). Also, gnoll.roll('1d6', builtins = True, mock = 1) segfaults.

Change Type

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Test Coverage (Additional test(s) without any extra code)
• Documentation Improvements
• Code Quality / Maintenance

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation & I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I give my permission for my code to be used in this project under this license and any future license terms

[github-actions]

Thank you for opening a pull request to GNOLL! As soon as the core tests pass and someone approves your pull request, you'll be all ready to merge!

[ianfhunter]

Code looks good to me. There's only one minor improvement to argparse i can see, but it's trivial, so there's no need to adjust it unless you want to.

Some other notes

• I'm just going to fix up some style deltas highlighted by the github action linter. A lot of these are a bit over-kill, but the style compliance on the repo is high so i'll make it fall in line.
• I see the javascript test is failing. It's definitely unrelated to this PR, but i'll make a note to file myself an issue to investigate (update: Various github actions are failing #442)
• Thanks for your feedback on documentation and the segfault - I will also log these to be investigated (Update Bugs raised in #441 #444)

Thanks for your contribution!

[ianfhunter]

suggestion (non-blocking): You may be able to call this without the args object - I think argparse will automatically collect them for you - then you would be able to remove the parsing code

Suggested change

	a = p.parse_args(args)
	a = p.parse_args()

[Kodiologist]

That's true in the usual case, but I figured that allowing parse_cmdline_args to be called with an argument would be convenient for testing. Then you don't have to mock sys.argv.