Pysheds Part 2

Summary

This merge completes the migration from TauDEM to pysheds. The main changes to the package are in the segments and models/staley2017 modules. Respectively, these implement stream segment networks, and the debris-flow probability models. Previously, the staley2017 module included functions that calculated earth-system variables for a set of stream segments, but these have been moved to the segments module. The Segments class has been given various new properties/attributes that facilitate the computation of these variables. The Kernel class (formerly an internal class of the segments module) has also been moved into its own module.

Several other misc additions include:

• A module to convert between different slope measurements
• The Segments class can now export stream segments to GeoJSON
• The staley2017 module now solves the probability equation in both the forward and reverse directions
• The Raster class include several new properties to describe pixels (pixel_area, resolution, etc)

Two-part merge

This is the second and final merge request dealing with the migration to pysheds. The pipeline tests have been restored and should now pass for all modules.

Notes for Reviewer

• The kernel module contains no new content - it's a direct copy-paste from the segments module
• segments and staley2017 have been heavily altered - probably easiest to just review them from the top, rather than comparing to the previous version

Closes #44 (closed), #45 (closed), #47 (closed)