first cut at logging instead of printing. Might need to bring back print...

... statements for backward compatibility?

After doing this, I started playing around with logging here: https://github.com/dblodgett-usgs/pyGDP/compare/logging

Works nicely. We have a bit of work to do to get this working as it was for pyGDP folks, but it is a way better situation for the future. 

@kwilcox, Any argument against eliminating the if verbose than print stuff?