[autofit] Add support for Avestan script. * src/autofit/afblue.dat: Add blue zone data for Avestan. * src/autofit/afblue.c, src/autofit/afblue.h: Regenerated. * src/autofit/afscript.h: Add Avestan standard character. * src/autofit/afranges.c, src/autofit/afstyles.h: Add Avestan data.