return status messages to gearman client

This checkin is to return a correct job status messages to the gearman
client.  It wasn't working before due to this gearman-java issue
https://bugs.launchpad.net/gearman-java/+bug/1126496

src/main/java/hudson/plugins/gearman/StartJobWorker.java
src/main/java/hudson/plugins/gearman/StopJobWorker.java
    Updates to return job error, warning, and success results to gearman client.
    Would like to point out that gearman java<->python translation doesn't work quite
    right.  I believe the python implementation of the gearman worker never
    sends exception messages back to the client

src/main/java/hudson/plugins/gearman/example/StartJobClient.py
src/main/java/hudson/plugins/gearman/example/StopJobClient.py
    Update examples to show how to extract messages

pom.xml
    Updated developer info

Change-Id: Ie8d82be8a8e7c34bc368efda953d5ddfb9547e01