Added argparser and --debug flag option

With the ArgumentParser, we can now add new command line flags as needed.  The
first flag added was a --debug option, which will enable debug output in the Map
and Game classes (for now).  This will default to false unless the flag is specified.

To test:
1. Run 'python bitfl.py'
2. N for New Game
3. Confirm that debug messages do not show
4. Q, then Q to quit
5. Run 'python bitfl.py --debug'
6. N for New Game
7. Confirm that debug messages show up
8. Q, then Q to quit