Adds a fat jar

This is the first release that can be used in bullet-service since it includes the fat jar. The backend should depend on the thin artifact as normal if you're building a jar-with-dependencies yourself. If you're plugging in the jar into your backend, you should use the fat jar.

First Release!

The first release for using Apache Pulsar as the pluggable PubSub layer. Point to com.yahoo.bullet.pulsar.PulsarPubSub as your PubSub class name in the settings.