Port existing benchmark logic

[markerikson]

Since reduxjs/react-redux#1008 was reverted, we should start out by copying the entire benchmarks folder over to the root of this repo to start off.

[cellog]

done. @markerikson @timdorr

Next, I'm going to extract the fps-emitter code into a private package we can import into each benchmark

[cellog]

done. now we can make beautiful new benchmark babies

[markerikson]

Okay, I'd say this is taken care of.