Manage verbosity of plugins

Issue raised by lots of logging.info and logging.debug messages from dezing plugin. Not restricted to 'dezing' but really any plugin whether C or Python.

Can the logger be configured with some more levels like logging.verbose that can be used for greater debugging and then you can just disable that level, instead of removing useful (to the plugin developer) debugging statements and having to put them back in again later when debugging is required? Since you (mark) explained the great utility of the Python logging facility I am less inclined to manage this by 'verbose' level inside my plugins, but prefer to use logger levels.