[Gridmix] Gridmix should provide a tool to compare and analyze Gridmix runs

After running Gridmix, users manually process simulated job history logs (probably using Rumen) and then use some external tools to analyze it, compare it with either the original job history files or with simulated jobhistory files of other Gridmix runs and generate reports. It would be nice if Gridmix comes bundled with a set of tools to do this transparently.