* mpeg/psi.h, dvb/si.h: Add descXX_validate() functions. * mpeg/psi_print.h: Validate descriptors before accessing them. * mpeg/psi.h: Avoid duplicate copies of the CRC32 table. * ALL: Make sure we return booleans. * dvb/si.h: Add support for DVB character sets. * dvb/si.h: Add content delivery descriptors 0x43, 0x44 and 0x5a. * dvb/si.h: Add VBI teletext descriptor 0x46. * examples/dvb_print_si.c: Add support for charset conversion via iconv.