Enhancements to ROOT performance benchmarking.

As software development grows in size and complexity, industry best practices include extensive quality testing often done at regular intervals or before a change is accepted into the codebase. ROOTBench is a continuous performance monitoring system for ROOT. This project sets out to enhance and improve ROOTBench by adding new feature (FlameGraphs) for inspecting the performance analysis of ROOT, extending new benchmarks and improving a library in rootbench.git.