This PR does 3 thing, each in a separate commit:

• Formats all code with Black (black)
• Formats all code with Black with an increased line limit of 100 characters (from the default 88) (black --line-limit 100)
• Formats all code with Black with an increased line limit while removing trailing commas (black --line-limit 100 -C)

In each commit some edge cases were by hand removed to retain the best readability. The code now fully follows Black formatting.

The 100 character line limit was chosen because it increases readability by offering more code in a single view and allows for slightly longer (and thus more descriptive) variable names without expanding code to multiple lines.

The trailing comma handling by Black is is worth explaining a little. If Black detects a trailing comma, such as

dict1 = {
    a: 1,
    b: 2,
}

it won't format the code to a single line. But if it doesn't detect a trailing comma, it does. So

dict1 = {
    a: 1,
    b: 2  # Note no comma here
}

becomes

dict1 = {a: 1, b: 2}

This way you can control if you would like your code to stay in multi-line or be reduced to a single line.

@quaquel Could you let me know if you A) agree with the increased line limit of 100 characters and B) find that this improved readability generally? (I checked everything by hand but just for sure)

(please let me merge if everything is ok)