Refactor / restructure

[sgoodm]

Entire codebase is currently in a single Python file that is essentially just a final proof-of-concept / prototype. We would likely benefit (even if only in terms of readability) by breaking some of the functions out into a class in a separate file.

This would be a good opportunity to make sure code is well organized and documented with comments/docstrings.

[sgoodm]

Eventually we may want to create a dedicated package for extracting spatial features from OSM links so that this can be applied to other projects and used by other folks.

[sgoodm]

I've done a fair amount of cleaning up, documenting code, etc. but may still want to explore viability of classes and refactoring some components (and creating a dedicated package)