update mqttd main.c, add mosquitto publisher and subscriber

guowenxue

2019-06-25 02294c1c430ab80bd4543af28f867c5c2927e5c1

tools/rpi_crosstool.tar.bz2 does not exist in tree c744e6f910cbaad2e8a7e5ba8b18f4e73d5e5024