Avalon-dev

*    for some reason network down. one simple cgminer command:
      "cgminer -o 127.0.0.1:8888 -O fa:ke --avalon-options 115200:32:10:50:256"
    can idle the avalon for safe power and protect chip
This is used at /etc/init.d/cgminer under OpenWrt. but I think it's useful/easy idle the Avalon.

*   if hash_count == 0; reinit avalon, fix the 0MHS bug
   use the max value of temp1 and temp2 for fan control