Function convertToString

tools/excelRTD/RTDServer.cpp:319–323

namespace {
  std::string convertToString(const VARIANT& value) {
    std::stringstream os;
    os << _bstr_t(value.bstrVal, true);
    return os.str();
  }

  std::string getSafeArrayElementAsStr(SAFEARRAY **Strings, long idx) {
    VARIANT value;