TODO items for biTStream. The items are not ordered by importance
so if you like something just do it and send a patch.

- Add support (parser, generator, example) for these MPEG descriptors:
  - Descriptor 0x21 MuxCode_descriptor
  - Descriptor 0x22 FmxBufferSize_descriptor
  - Descriptor 0x24 content_labeling_descriptor
  - Descriptor 0x25 metadata_pointer_descriptor
  - Descriptor 0x26 metadata_descriptor
  - Descriptor 0x29 IPMP_descriptor (defined in ISO/IEC 13818-11, MPEG-2 IPMP)

- Add generators and example usage for these DVB descriptors:
  - Descriptor 0x4a: Linkage descriptor
  - Descriptor 0x6a: AC-3 descriptor

- Add support (parser, generator, example) for these DVB descriptors:
  - Descriptor 0x45: VBI data descriptor
  - Descriptor 0x49: Country availability descriptor
  - Descriptor 0x4b: NVOD_reference_descriptor
  - Descriptor 0x4c: time_shifted_service_descriptor
  - Descriptor 0x4f: time_shifted_event_descriptor
  - Descriptor 0x50: component_descriptor
  - Descriptor 0x51: mosaic_descriptor
  - Descriptor 0x53: CA_identifier_descriptor
  - Descriptor 0x57: telephone_descriptor
  - Descriptor 0x5b: multilingual_network_name_descriptor
  - Descriptor 0x5c: multilingual_bouquet_name_descriptor
  - Descriptor 0x5d: multilingual_service_name_descriptor
  - Descriptor 0x5e: multilingual_component_descriptor
  - Descriptor 0x60: service_move_descriptor
  - Descriptor 0x61: short_smoothing_buffer_descriptor
  - Descriptor 0x62: frequency_list_descriptor
  - Descriptor 0x63: partial_transport_stream_descriptor
  - Descriptor 0x64: data_broadcast_descriptor
  - Descriptor 0x65: scrambling_descriptor
  - Descriptor 0x66: data_broadcast_id_descriptor
  - Descriptor 0x67: transport_stream_descriptor
  - Descriptor 0x68: DSNG_descriptor
  - Descriptor 0x69: PDC_descriptor
  - Descriptor 0x6b: ancillary_data_descriptor
  - Descriptor 0x6c: cell_list_descriptor
  - Descriptor 0x6d: cell_frequency_link_descriptor
  - Descriptor 0x6e: announcement_support_descriptor
  - Descriptor 0x6f: application_signalling_descriptor
  - Descriptor 0x70: adaptation_field_data_descriptor
  - Descriptor 0x71: service_identifier_descriptor
  - Descriptor 0x72: service_availability_descriptor
  - Descriptor 0x73: default_authority_descriptor
  - Descriptor 0x74: related_content_descriptor
  - Descriptor 0x75: TVA_id_descriptor
  - Descriptor 0x76: content_identifier_descriptor
  - Descriptor 0x77: time_slice_fec_identifier_descriptor
  - Descriptor 0x78: ECM_repetition_rate_descriptor
  - Descriptor 0x79: S2_satellite_delivery_system_descriptor
  - Descriptor 0x7a: enhanced_AC-3_descriptor
  - Descriptor 0x7b: DTS descriptor
  - Descriptor 0x7c: AAC descriptor
  - Descriptor 0x7d: XAIT location descriptor
  - Descriptor 0x7e: FTA_content_management_descriptor
  - Descriptor 0x7f: extension descriptor
    - Add support for extension descriptors