[bdf] Simplify comment collection or lack thereof. BDF comments are neither actually collected nor retrieved. There is no need to be fancy with delimiters. * src/bdf/bdflib.c (_add_bdf_comment): Delimit comments with zeros... (bdf_load_font): ...and do not null-terminate comments additionally. (_bdf_parse_glyphs): Check if comments are kept, which they are not. (_bdf_parse_start): Minor clean up.