Standardized on specific continuation indent style

Entirely fixes PEP-8 errors E121, E122, E126, E127, and E128.

From now on, when a function call is too long to fit on one line, it
should look like one of the following:

really_long_function_call(
    single_argument)

function_call(
    first_argument,
    second_argument,
    third_argument
)