Wrap Event

Hey @marksteele !!! :smiley:

This patch wrap the json object as an [event bean](http://esper.codehaus.org/esper-4.9.0/doc/api/com/espertech/esper/event/map/class-use/MapEventBean.html)

I tested it using the esper-amqp test suite 
but couldn't test it properly using interruptus..

Before merge it please let me know if it works fine for you...


Cheers