(struct CONCORD_Object_Header): New structure.

(struct CONCORD_Object_Header): New structure.
(CONCORD_OBJECT_TYPE_NULL): New macro.
(CONCORD_OBJECT_TYPE_C_STRING): New macro.
(CONCORD_OBJECT_TYPE_INT): New macro.
(CONCORD_OBJECT_TYPE_DS): New macro.
(CONCORD_OBJECT_TYPE_GENRE): New macro.
(CONCORD_OBJECT_TYPE_FEATURE): New macro.
(CONCORD_OBJECT_TYPE_INDEX): New macro.
(CONCORD_OBJECT_TYPE_OBJECT): New macro.
(struct CONCORD_DS_Table): Add new member `header'.
(concord_open_ds): Setup ds->header.
(struct CONCORD_Genre_Table): Add new member `header'.
(concord_ds_open_genre): Setup ds->header.
(struct CONCORD_Feature_Table): Add new member `header'.
(concord_genre_open_feature): Setup ds->header.
(struct CONCORD_INDEX_Table): Add new member `header'.
(concord_genre_open_index): Setup ds->header.