message: nmea_gps: Fix iterator
  Small fixes for new nmea_gps code.  Fixed an iterator which could get
  dereferenced incorrectly, and changed an auto to an explicit type.
diff: @@ -234,7 +234,7 @@ void NMEAGPS::_parse_gpgsv(const std::string& sentence)
  /* Add to the back of satmap, remove any matching prn */
  _mtx_satlist.lock();
  auto sit = _satlist.begin();
  - do
  + while(sit != _satlist.end())
  {
  /* Remove */
  if ((*sit).prn == sat.prn)
  @@ -242,7 +242,8 @@ void NMEAGPS::_parse_gpgsv(const std::string& sentence)
  sit = _satlist.erase(sit);
  break;
  }
  - } while(++sit != _satlist.end());
  + ++sit;
  + }
  /* Add satellite to the end */
  _satlist.push_back(sat);
  @@ -458,7 +459,7 @@ std::string satellite::__str__()
  std::string NMEAGPS::__str__()
  {
  std::ostringstream oss;
  - auto sats = satellites();
  + std::vector<satellite> sats = satellites();
  size_t qsz = getMaxQueueDepth();
  oss << "NMEA GPS Instance" << std::endl
  << " Parsing: " << (isRunning() ? "T" : "F") << std::endl
  