Point gen crall

@Vinnie

This is a set of changes I've made on top of your code. Please review and ask questions as necessary. General changes are:

1. Minor code cleanups, ran black and did linting fixes.
2. Use status code from the T&E geojson instead of assuming everything is always positive.
3. Use cross-machine logic in the docstr example blocks (these should work on your machine too)
4. Add the draw_region command to the docstr example blocks
5. Add an "ellipse" method in addition to the "box" method.
6. Renamed box_size and time_pad to size_prior and time_prior
7. For the box_prior I'm reusing existing logic in util_resolution so the user can specify sizes in physical units. I.e. the default is now 20.06063 x 20.0141229 @ 10mGSD