SLING-4494 - Performance: update performance test framework to allow comparison of results

* performance testing features which allow to not only log tests run time but also compare
them and fail in case a certain threshold ratio is surpassed

(applied patch sent by Vlad B─âilescu - closes #69)

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1666250 13f79535-47bb-0310-9956-ffa450edef68
5 files changed