[cff] Allow SIDs >= 65000. * src/cff/cffload.c (cff_charset_load): Fix change from 2009-03-20: The threshold for SIDs is not applicable here. I misinterpreted the `SID values 65000 and above are available for implementation use' sentence in the CFF specification. Problem reported by Ivan Ninčić <inincic@pdftron.com>.