[autofit] Use better blue zone characters for lowercase latin. The number of lowercase characters for computing the top flat blue zone value was too small (in most cases only `x' and `z'). If one of the two characters has a large serif, say, it can happen that FreeType must select between two different values, having a 50% chance to use the wrong one. As a result, rendering at larger PPEM values could yield uneven lowercase glyph heights. Problem reported by Christoph Koeberlin <christoph@koe.berlin>. * src/autofit/afblue.dat (AF_BLUE_STRING_LATIN_SMALL): Replaced with... (AF_BLUE_STRING_LATIN_SMALL_TOP, AF_BLUE_STRING_LATIN_SMALL_BOTTOM): ... New, extended sets. (AF_BLUE_STRINGSET_LATN): Updated. * src/autofit/afblue.c, scr/autofit/afblue.h: Regenerated.