Implement the configuration debug option

[captainceramic]

This shouldn't be very difficult. At the moment the configuration option for debug is not implemented. I think this could quite easily be implemented by allowing the overall logging level to be set to debug if this was set in the configuration.

The complication here is that it is not clear exactly at what point this logger level should be set. At the moment the logging level is set in the the logger definition in the __init__.py for the package.