[Improvment] Personalize the ribbon plot renumbering the residues

[micmar15sr]

I would like to thank you for providing this tool and its open-source code. I have used Alphabridge to generate a plot for a complex where I analyzed two protein domains instead of two whole proteins. I was wondering if it might be possible to add an option to renumber the sequences in the plot. For instance, by shifting the residue numbering of a chain by adding a constant value.