[autofit] Add blue-zone support for Gurmukhi script. This essentially moves the Gurmukhi script from the `Indic' hinter to the `Latin' hinter. * src/autofit/afblue.dat: Add blue zone data for Gurmukhi. * src/autofit/afblue.c, src/autofit/afblue.h: Regenerated. * src/autofit/afscript.h: Add Gurmukhi standard characters and move data out of AF_CONFIG_OPTION_INDIC block. * src/autofit/afranges.c: Move Gurmukhi data out of AF_CONFIG_OPTION_INDIC block. * src/autofit/afstyles.h: Update Gurmukhi data; in particular, use AF_WRITING_SYSTEM_LATIN.