Make Py5Color objects pickle-able?

[hx2A]

@villares suggested we make some adjustments to the Py5Color to make it pickle-able:

#763 (reply in thread)

But there's a reason why the objects retain links to their creator Sketch. But that link isn't so important to prevent pickling. How can I fix this?

[villares]

I kind of remember when you added Py5Color you mentioned something about adapting the representation to the current color mode. And I remember thinking I wouldn't mind if the color object "talked" in reference of the color mode when it was created. I thought it would be even more useful in debugging... (retaining the condition of creation).