dev_requirements.txt: point fontMath to master branch as ufo3 was merged and deleted; use Cython >= 0.24
dev_requirements.txt: point fontMath to master branch as ufo3 was merged and deleted; use Cython >= 0.24

googlei18n/fontmake,googlefonts/fontmake,googlefonts/fontmake,googlei18n/fontmake