README: sample-bisync-framed

This is a simple example demonstrating use of a 9198 in framed bisync
mode.  This sample consists of one application: a data loopback.
NOTE: External clocking must be provided as the 9198 custom hardware does
not support generation of transmit or receieve clocks.

The first argument for the sample is the SeaMAC serial port desired to perform
the operations on.  The application can optionally take two more arguments:
message size and iterations.

$ bif /dev/ttySM0 32 5

The message(s) sent by the application consist of the specified number of data 
bytes cycling from 2 to 255.  No data checking is performed.

