Reformat hydromet_stratified.py Following PEP8

[ShaneMPutnam]

All local variables and functions should be lower case and for readability, all functions should have a description even if they seem self-explanatory.

[ShaneMPutnam]

Also, use descriptive variable names when possible. Instead of calling a variable "R" use "rainfall_total" and then add the units and additional information to the docstring.