break up argparse setup and add quiet/verbose mode

closes issue #57: breaks up argparse setup into more manageable chunks.
should there be a need to add a new mode (e.g. config management mode)
it should be more obvious how to do this.

closes issue #61: implements a more intuitive logging level system,
described in #61.  this commit does not actually change existing levels
of any existing messages, mentioned in #62