CSV output support for NNThroughputBenchmark

Now the NNThroughputBenchmark has only console result output, i use this benchmark a lot and it's more convenient to have ability to write benchmark results in csv file. 

This change add BenchmarkOutputWriter class, which prints any benchmark results in csv file, this entity could work with any benchmark. To implement this feature in benchmark, @Parameter annotation was added in benchmark fields.

I think this option very helpful for community