Matching engine performance tests using JMH

This adds microbenchmarks for the matching engine using JMH.

To run it, type:

  mvn install

and then:

  java -jar parity-perf-test/target/microbenchmarks.jar

Signed-off-by: Pekka Enberg <penberg@iki.fi>
Merge pull request #1 from penberg/perf-test

Matching engine performance tests using JMH