huey: Internal maintenance specification

This is a concrete class inheriting from the base ColorModel class. It implements the red-green-blue color model. It doesn't have much work to do, since the Color object uses the RGB model as its internal representation.

# - - - - -   c l a s s   R G B M o d e l

class RGBModel(ColorModel):
    """Represents the red-green-blue color model.
    """