Don't assume an event bus message has an address property

[lance]

This commit breaks backwards compatibility.

#7

The fix requires that the event bus always call jMsg.address(), which hasn't always existed. Therefore, with older versions of vert.x users will see this message.

org.dynjs.exception.ThrowException: TypeError: not callable: [DerefRef: value=undefined; ref=[Reference: name=address; base=org.vertx.java.core.eventbus.impl.JsonObjectMessage@809f86c (org.vertx.java.core.eventbus.impl.JsonObjectMessage)]]

This would cause breakage for users of lang-rhino 2.0.0-final or any recent SNAPSHOT of lang-rhino or lang-dynjs who upgrade their language module to 2.1 for rhino or 1.0 for dynjs, but don't update their vert.x. Admittedly a silly thing to do, but there you go.