Functions:-Gather and dispatch DGNSS data from Ntrip broadcasters. Notes based on codec as of Tue Apr 6 10:17:55 2010 -0400. static char *ntrip_field_iterate(char *start, char *prev, const char *eol) Extract individual fields from the STR data block using ';' as the separator but handling string-embedded ';' characters correctly. static void ntrip_str_parse(char *str, size_t len, struct ntrip_stream_t *hold) Break an STR data block down using ntrip_field_iterate() and store the relevant details in an accumulation buffer. static int ntrip_sourcetable_parse(int fd, char *buf, ssize_t blen, const char *stream, struct ntrip_stream_t *keep) Parse a block of ntrip data by passing the STR data to ntrip_str_parse().Return a 0 on success or -1 on any of the many possible failures. static int ntrip_stream_probe(const char *caster, const char *port, const char *stream, struct ntrip_stream_t *keep) Send a request to the broadcaster for a block of correction data.If successful, return the result of parsing the table. On error return -1. static int ntrip_auth_encode(const struct ntrip_stream_t *stream, const char *auth, char buf[], size_t size) Check the authorisation of the stream and return 0 if there is none or it is basic. Return -1 in all other cases. static int ntrip_stream_open(const char *caster, const char *port, const char *auth, struct gps_context_t *context, struct ntrip_stream_t *stream) Check the authorisation of the stream and if successful, try to connect.On connection, try to read data and test for various errors.On success, return the socket number, on error return -1. int ntrip_open(struct gps_context_t *context, char *caster) Try to establish a connection to the ntrip server. On success, return the socket number. Signal error with a return of -1. void ntrip_report(struct gps_device_t *session) If we have not contacted the server already and we have at least 10 fixes, send a report to the server and set the flag, so we don't do it again.