Add Poetry support

[queue-miscreant]

Since it seems like the author wants to get this project into better shape, I might as well do my part by fixing up the package management.

This PR:

• Adds a pyproject.toml utilizing poetry (and generates a poetry.lock file)
• Moves source files into dcolor/ and exposes names via dcolor/__init__.py
• Fixes examples, when run using poetry run python
  • Adding ".." to sys.path only works when running python from examples/. Poetry at least provides the guarantee of matching to the correct virtual environment, and works from anywhere in the project tree
• Runs black to format all Python files in the project
• Removes the __pycache__ and .DS_Store files (filesystem ephemera), and adds them to the .gitignore

[hernanat]

thanks! admittedly I don't know much about the python ecosystem these days, so was asking some colleagues for their input on this as well. just one comment

[queue-miscreant]

Incidentally, while working on one of said other branches, I got interested in generating the images in the README programmatically. It seems like images/hsvcolor.png is incorrect. When I generate it, I get something identical to dcolor.png visually (although the binary contents differ).

Tool used: https://www.diffchecker.com/image-compare/

[queue-miscreant]

@hernanat Wanted to make sure you saw the commits I added to this. I also left a big list of things I suggested working toward in the issue linked above (#5). I have a branch based on this one which has a more imperative feel (and makes it easier to generate examples for the README), but I don't want to make this PR any harder to review.

[hernanat]

@hernanat Wanted to make sure you saw the commits I added to this. I also left a big list of things I suggested working toward in the issue linked above (#5). I have a branch based on this one which has a more imperative feel (and makes it easier to generate examples for the README), but I don't want to make this PR any harder to review.

hey there! Thank you, yes I did see. Sorry -- I have been on vacation & traveling a bunch. I will try to get to all of this in the next few days when I have some free time.

[hernanat]

thank you again for all of this!