* Add many new c++ catch2 performance benchmarks.
* inline splitmix64 from boost, splitmix64 is not always available in boost. fun fact, this version is ~twice as fast
* reduce intensity of memory pressure test, target 200MB usage.
* new bench compound; accept suggestion from code review
* bench MolToCXSmiles
* Update Code/Bench/stereo.cpp
* impl first part of the suggestions from code reveiw
* impl second part of the suggestions from code reveiw
