Add benchmarking framework for testing on mass amount of events.

@benbjohnson I'm interested in your thoughts on this.

This isn't complete, but is the beginning of a benchmarking framework that creates a table with schema, populates it for N events, and yields the server.  

You can pass the path to the benchmark so you don't have to regenerate a large dataset when running consecutive benchmarks. 

Future work on this will be to make saner events (like generating IDs within a set so there's >1 event per ID), and add tests and benchmarks that operate on a larger order of magnitude of events (like >1 million) generated from this method.