global command flags

This pull request addresses issue #62.

This is still a work in progress, I haven't finished yet with the unit testing of the BaseCommand class.  There is also a known issue with the BaseCommand constructor calling the addGlobalCommandArgument method incorrectly, preventing the test suite from running.  Once this work is done and the unit test suite passes, I will squash my commits down and update this PR with a note confirming that this is ready for merge.