Using logging instead of print

[Elango Cheran]

For the test driver and test data generator in Python, we should use logging instead of just printing to the console.

At the least, it's equivalent. But the potential benefits are:

• logging methods (ex: logging.debug(), logging.error()) allow us to indicate what severity a statement is
• we can control what level we view logs at for testing mode, debugging mode, and production mode
• we can configure the format of the messages if needed (add timestamps, etc or not)

[Elango Cheran]

Fixed by #136