Add lightd code, auto light can work by infrared and relay now

guowenxue

2021-01-23 8fee9f5701ffdcc17e1f0f2453d495fe849d1fe2

 apue/1.File_IO/ds18b20.c

@@ -116,5 +116,7 @@
    /* convert string value to float value */
    *temp = atof(ptr)/1000;
   
    close(fd);

    return 0;
}