Create shaded jar and introduce joda-time as SimpleDateFormat is not threadsafe

Hello,

I liked to have a shaded version of the formatter to easily make a drop-in in Jenkins via the `java.endorsed.dirs` directive, just put the logging.properties and the shaded-jar in e.g. `$JENKINS_HOME/lib` and extend `JAVA_ARGS`

```
JAVA_ARGS="$JAVA_ARGS -Djava.endorsed.dirs=$JENKINS_HOME/lib -Djava.util.logging.config.file=$JENKINS_HOME/lib/logging.properties"
```

Without shading I had to copy the dependencies as well. As SimpleDateFormat is *not threadsafe*, I included joda-time in the mix for this. It would be great if you could release a new version in the near future, otherwise I go with a vendor-release.