Let the load generators scale linear

[bvonheid]

The load generator divided the data volume by three and rounded the result. Thus, e.g., for load 2, 3, and 4 the same number of iterations are performed and result in the same produced data rate. Now the data volume is taken and not divided. Further, the data volume starts at one to produce data to have a ratio scale and data volume of 0 is the absolute zero.

Further, the describe data volume in the Wiki is not correct. The StreamProducer call 3 times the publish method and yielded a throughput of 1140 for data volume 0 and both streams.

With the proposed change the new throughput is: throughput = 1140 * DATA_VOLUME or for one Data Stream: throughput = 570 * DATA_VOLUME