send args to roodi_task will make it easier to add custom configuration

This change will make it easier to use a custom configuration from a rake task.

Before you would have specify the name and pattern just to be able to include the configuration
  RoodiTask.new :roodi, nil, "config/roodi.yml"

After you will just pass it the the config variable
 RoodiTask.new :config => "config/roodi.yml"

This change will not effect users who are not passing in any parameters.