feature:

1.Add spdlog to save log file
2.Add program options to connect specific broadcast code and decide whether to save log file
3.Add comments in readme for windows 64-bit project compilation

sdk_core/include/livox_sdk.h

@@ -56,6 +56,11 @@ bool Start();
  */
 void Uninit();
 
+/**
+* Save the log file.
+*/
+void SaveLoggerFile();
+
 /**
  * @c SetBroadcastCallback response callback function.
  * @param info information of the broadcast device, becomes invalid after the function returns.