Add a color surfaces "fromribbon" option

[Tom Goddard]

Want to color a molecular surface to match the ribbon color. There is already a "fromatoms" option but when the non-carbon atoms are different colors this is rarely what is needed. The "fromribbon" option will make it easy to make the chain surface colors match the ribbon colors.

This option would help with this user question

From: HONG ZHAN via ChimeraX-users <chimerax-users@cgl.ucsf.edu>
Subject: [chimerax-users] Generate surface from a model using user defined color
Date: October 14, 2022 at 6:43:40 PM PDT
To: ChimeraX Users Help <chimerax-users@cgl.ucsf.edu>

Dear all, 

I would like to generate surface using my model but I want to keep the color as I defined. My protein contains only one chain so that when I ran Surface command, it generated surface with one color... Is there a way to generate surface to keep my defined color? 

Super thanks!
Hong