blazer_soi: blazer driver, serial port over tcp/ip

This is a version of blazer that allows the use of a ethernet to serial device, also called YPort.
Such a device allows a serial port to be connected to an existing ethernet network, and uses tcp to access the serial port. An example of this device is provided by Ethersex Project (http://www.ethersex.de); this driver extension has been tested with it.