[sfnt] Make `head' timestamps unsigned. It's been more than 2^31 seconds since 1904. * include/freetype/tttables.h (TT_Header): Change field types. * src/sfnt/ttload.c (tt_face_load_generic_header): Updated. 2018-10-27 Alexei Podtelezhnikov <apodtele@gmail.com> Revert: Align...