[symfont] Write code to write optimized code for green-derived pens
[symfont] Write code to write optimized code for green-derived pens

Eg.:
printPen('MomentsPen',
         [('area', 1),
          ('momentX', x),
          ('momentY', y),
          ('momentXX', x*x),
          ('momentXY', x*y),
          ('momentYY', y*y)])

fonttools/fonttools,googlefonts/fonttools