Support multiple nodes #24
Description
esperf currently only works correctly when the cluster has one node. This issue is about adding support for multiple nodes.
Our first approach will be to add the node-name to all metrics. Thus, instead of having: cpu_baseline_poisson_1.csv we would have cpu_baseline_node-1_poisson_1.csv. Leaving the actual metric name in the beginning and the experiment id at the end of the file name.