implement leap year code in XS calculate dow and doy in rd2greg when asked (speeds up _calc_local_components)
implement leap year code in XS
calculate dow and doy in rd2greg when asked (speeds up _calc_local_components)

chansen/DateTime.pm,chansen/DateTime.pm,autarch/DateTime.pm,1nickt/DateTime.pm,autarch/DateTime.pm,1nickt/DateTime.pm,chansen/DateTime.pm,1nickt/DateTime.pm