Groovy script to compute peptide variants from codon variants

Jalview 2.11 computed and added derived peptide variants from codon variants, Jalview 2.11.1 doesn't, instead shows codon variants virtually, and computes peptide consequences on the fly only. This removes the ability to colour or filter by the peptide variants.

Pending a change to the application to meet this need, provide a Groovy script to do it.