0.5.2

• 2fef392 - Avoid java.lang.NoSuchMethodError: java.util.concurrent.Executors.newWorkStealingPool()Ljava/util/concurrent/ExecutorService; error in Java 7
• 95ce467 - Avoid java.lang.ClassNotFoundException: org.apache.log4j.or.RendererMap in JBoss application server, adding log4j library