Update tool to allow specification of additional codepoints.
Update tool to allow specification of additional codepoints.

This gets called from the emoji makefile.  Occasionally we build fonts
without the supporting data present, and this lets us hack in additional
codepoints to build these tests.

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