Add option that parses a comma separated or json traffic pattern and converts it into an output stream.

[fruffy]

Currently, Goben measures the traffic stats and put them in a log file. We need to convert this file (or instead of converting, just send the statistics as a stream directly) to an output stream.

A sample pattern can be found in https://github.com/dcgym/iroko/blob/master/dc_gym/inputs/fattree/stride4_data

This can also be done as a python wrapper of the traffic generator.