Make web generation code ok with limited subsets of the fonts.
Make web generation code ok with limited subsets of the fonts.

This makes it possible to run the code on only some fonts (e.g. only
the emoji) while debugging.

dougfelt/nototools,moyogo/nototools,googlefonts/nototools,googlei18n/nototools,anthrotype/nototools,googlei18n/nototools,googlefonts/nototools,googlefonts/nototools,googlefonts/nototools,anthrotype/nototools,dougfelt/nototools,googlefonts/nototools,moyogo/nototools,anthrotype/nototools,dougfelt/nototools,googlei18n/nototools,moyogo/nototools