Logging, argparse, pylint and misc

[QSchulz]

Hi,

• You'll find a handful of commits to fix some misc mistakes,
  • Then a commit to flatten the conditions to have less indentation and make the code (hopefully more readable),
  • The YAML parsing errors now print the full context and help figuring out exactly where the error is in the parsing (line, column AND actual content of the line),
  • Log messages are now handled by the logging module which allows people to make a build more or less verbose depending on their need,
  • Docopt is replaced by argparse as it's not been updated in more than 6 years and argparse is part of Python internal libraries, this allows us much more feature-full argument parsing with integrated checking if need be,
  • Fixed a few issues reported by pyLint,

While the changes in behavior are overall pretty minor IMO, sometimes the diff is rather big and unreadable. It'd be super cool to have unit tests to guarantee a merge request hasn't messed up some rarely taken code paths. Maybe in another merge request, who knows :)

Let me know if there's anything to fix/not to your taste.

Quentin

[gangelop]

this also resolves #112

[Psycojoker]

Thx a lot for all those commits :)

I've ended up cherry-picking most of them (instead of merging, it ended up a bit confused because I've merged the other PRs before), from memory, the one I haven't picked up are:

• changing the default log level simply because I'm not sure about this one
• some pylint fix because I've just going to move the project to black
• maybe some duplicates with other PR?

Thx again :)