Implement or import pure python ray casting algorithm/point in polygon

[robmarkcole]

Prerequisite for #184

• https://en.wikipedia.org/wiki/Point_in_polygon#Ray_casting_algorithm
• https://github.com/search?l=Python&q=point+in+polygon&type=Repositories

Some options in https://gis.stackexchange.com/questions/7157/pure-python-library-for-geometry-operations

• sympy looks promising -> https://docs.sympy.org/latest/modules/geometry/index.html
• also https://turfpy.readthedocs.io/en/latest/index.html

[robmarkcole]

Try https://docs.sympy.org/latest/modules/geometry/polygons.html

This has required functionality and doesn't create any issue with dependencies or install

[robmarkcole]

Too complex, use mask approach instead