Fixes AMQ-4529: leveldb store NPEs when you send to a composite destination.

git-svn-id: https://svn.apache.org/repos/asf/activemq/trunk@1481013 13f79535-47bb-0310-9956-ffa450edef68
Add a little main class to the leveldb store module to make it easier to run a broker from your IDE.

git-svn-id: https://svn.apache.org/repos/asf/activemq/trunk@1481014 13f79535-47bb-0310-9956-ffa450edef68