Updated javassist

Javassist was updated from 3.22.0-GA to 3.23.1-GA

Reflection method executor

First version to include the reflection method executor. Javassist method executors need to be tweaked. In micro-benchmarks Javassist method executors are slower than reflection, this is likely due to casting or some other issue, issue will be explored further.

Multi threading support testing

Testing multi-threading support

Initial release

At 94% code coverage, should be good for now.