Added lots of restrictions to using keyword arguments at the public interfaces (v2.0.0)

[simon-ritchie]

Since version 2.0.0, lots of restrictions were added to using keyword arguments at the public interfaces. If you use a positional argument at the restricted public interfaces, the apysc raises an exception.

This change is being made to maintain long-term modifiability and extensibility.

See also:

Any reason NOT to always use keyword arguments?