Update README.md
Added several relevant articles
- [The Basics of Java Generics](http://www.baeldung.com/java-generics)
- [The Traveling Salesman Problem in Java](http://www.baeldung.com/java-simulated-annealing-for-traveling-salesman)
- [How to Create an Executable JAR with Maven](http://www.baeldung.com/executable-jar-with-maven)
+- [Guide to java.util.concurrent.Future](http://www.baeldung.com/java-future)
+- [Guide to java.util.concurrent.BlockingQueue](http://www.baeldung.com/java-blocking-queue)
+- [Guide to CountDownLatch in Java](http://www.baeldung.com/java-countdown-latch)
