Add support for BITMAIN AntMiner devices

Bitmain Technologies Inc. is a new ASIC miner vendor, which specializes in research, development and sales for custom mining chips and miners. Our chip has been released and is very good high efficiency, and the AntMiner Solution with competitive price, is able to provide the most power effective mining solution today.
This submission provides support for AntMiner devices, including BitMain Multi Chain Mode and Single Chain Mode.
BitMain Multi Chain Mode support for AntMiner S Series devices.
BitMain Single Chain Mode support for Ant Miner U Series devices which is USB device.

According to your comments, we will revise the codes and we hope to get more guide and opinions form you.