color: drop the 'colorui' class Now that all logics formally bared by 'colorui' have been moved to the main ui class, that class is empty and can be dropped. As a nice side effect we can get rid of the baroque Initialization associated to it. There was much rejoicing.

color: move 'write-err' logic to the core ui class This is similar to what we needed for 'write', we move the logic from the extension to the core class. Beside the dispatch to 'win32print', we just apply label to the argument.

ui: extract low level part of 'write_err' in its own method Same as for 'write' and '_write' we needs it available for some of the color logic.

ui: extract buffer write from protect and timed 'write_err' output That subcall to 'self.write' is never doing actual write but only store things in buffers. So we do not need to protect it for exception not to time its execution. This will make it easier to extract a '_write_err' function as we did for 'write'.

color: move 'write' logic to the core ui class One more step, the support for writing color is not directly in core. No behavior change for the default case ('_colormode' = None). Here are the details of what we have to change to the core method: * apply to 'self.label' to input in the buffered case * dispatch to 'win32print' when applicable * apply to 'self.label' to input when applicable

ui: extract the low level part of 'write' in a dedicated function We are about to add some extra logic related to color. That logic will need to access the low level layer of ui doing the actual write to a stream. (eg: 'win32print'). We extract this logic into a private method for this purpose.