Update Client Lib for Java Robots

[Brian Kennish (Googler)]

Hey all, if you're developing a Java robot, you'll want to upgrade to
the latest client library at
http://wave-robot-java-client.googlecode.com/files/wave-robot-api-20090603.jar.

We just introduced a new event -- wavelet_self_added -- that fires for
every robot, regardless of whether the event has been registered or
not, to avoid the situation where a robot with a bad capabilities file
never gets sent an event. This change breaks event marshaling for
older clients.