Update logging levels for more appropriate log entries.

[jgreenemi]

Go through the package and change the logger messages so not everything's logged at Warning logging.warning('') level. This was done so that key stages could be identified in testing, as a result of my not setting up the StreamHandler beyond the defaults. Many of the Warning messages should be Info level, and the StreamHandler should be set to display them so when you run $ python setup.py you get useful outputs.

Can also create options for the user to have a FileHandler so logging output is kept in a file rather than just in the terminal buffer, but depends on whether this is a big user ask or not - could be overkill since the most useful logging messages will be errors and will display with the default settings anyway.