Add XML debug script, fix connection deadlock, and improve error handling

[cdheiser]

• Removed deadlocking when username/password are incorrect or the IP address won't accept a connection
• Raise different exceptions for connection failures vs. login is not working
• Added debugging script for parsing an XML on its own
• Refactored the test_connect.py script to use the same XML debug output
• Renamed test_connection.py debugging script to avoid confusion with unittests