2.0.0 - correct depth of import to match CPython; add to pypi

To use in CircuitPython, simply install the Adafruit CircuitPython Bundle.

To use in CPython, pip3 install adafruit-circuitpython-itertools.

Read the docs for info on how to use it.

What's Changed

• Prepared for adding to PyPI by @evaherrada in #17
• remove adafruit_itertools layer from import by @FoamyGuy in #16

Full Changelog: 1.1.10...2.0.0