microbench: move caliper to jmh

it's still a WIP, but it already works...

what I need to do is:
- make the runtime options better configurable through system properties
- export the reports into files so they can be better digested..

but it works!

since it has junit support as before, you can run it from your IDE (but only class-level, not method level).. or from the command line through `mvn -DskipTests=false test`.

Happy christmas :)