Ironed out kinks in plugin/driver loading and configuring.

Ironed out kinks in plugin/driver loading and configuring.

Highlights:

  * Plugin/Driver.setting_section attribute so subclasses don't need
    to construct it on their own (duplicate effort, and so, error
    prone).
  * Fixed self.wrap = True -> self.wrap = wrap bug in
    hooke.config.Setting
  * No longer alter hooke.config.DEFAULT_SETTINGS in
    hooke.hooke.Hooke.__init__()
  * Filled in Hooke.load_plugins()/.load_drivers() stubs.
  * Removed deprecated Hooke.driver_default_settings().
  * Commented out a lot of the old HookeFrame code.  I'll delete
    it as I go through and implement its functionality.