Move to Python 3 (#1)
Move to Python 3 (#1)

* Update "c" type code; make print calls; lint.

- The "c" type code is no longer supported by the `array` module so uses
  "B" instead, ie. "unsigned char"

- Python 3 contains `print()` as a function to be called rather than a
  statement

- Linters run:
  + black -l 80 .
  + isort --profile black .
  + flake8 --max-line-length=80 --ignore=E203,W503 .

* Replace deprecated `array.tostring()` call
richard-thomas/MetOffice_NIMROD