Add a benchmarking suite

[jmert]

Improvements/changes should be validated via a set of benchmarks before being committed. To do that, though, first a suite of benchmarks must be created and added.

• First level goal is to just provide a basic suite which can be run manually.
• Second level would be to add some performance assertions that compare pairs of benchmarks within the suite (such as the scalar calculation should be faster than a length-1 vector calculation).
• Third level is to provide a framework for running and summarizing the benchmarks across multiple architectures (i.e. compare personal laptop and desktop which have Intel vs AMD processors from different generations).