Use the reference implementation of JSR-353

JSR-353 (http://jcp.org/en/jsr/detail?id=353) has his final draft. Oracle provides an reference implementation that will be used in upcomming JEE7 specification.

I replaced net.minidev.json with the RI and removed the commons lang dependency. It will give the encoder a lower footprint.

Additional I added the hostname to source_host in the json_event.