Track performance benchmarks

[pipermerriam]

Benchmark results:

v1.0.0 release

Block serializations / sec: 1802.48
Block deserializations / sec: 1465.40
TX serializations / sec: 23371.21
TX deserializations / sec: 20408.96

Master @ f30fe1e

Block serializations / sec: 1891.86
Block deserializations / sec: 765.90
TX serializations / sec: 25249.98
TX deserializations / sec: 13829.94

After #57 @ cedba03

Block serializations / sec: 1869.49
Block deserializations / sec: 754.00
TX serializations / sec: 24482.09
TX deserializations / sec: 13933.05

v0.6.0 (691d1e1)

Block serializations / sec: 1584.33
Block deserializations / sec: 638.20
TX serializations / sec: 20081.98
TX deserializations / sec: 11416.72

After removal of python 2 support (d6af5a5)

Block serializations / sec: 1555.26
Block deserializations / sec: 663.43
TX serializations / sec: 21432.37
TX deserializations / sec: 10828.38

After removal of rlp.utils and conversion to use eth-utils (7ee1abf)

Block serializations / sec: 1795.98
Block deserializations / sec: 742.01
TX serializations / sec: 24321.49
TX deserializations / sec: 13368.13

[pipermerriam]

Worth noting that these benchmarks have a high error rate when compared to one-another since load on my machine will vary between runs, some may run during higher loads, etc. so take them with a grain of salt.