NPE on Thread.join() possible fix

This bug is hard to decipher mainly due to the thread being terminated somewhere before the thread.join is called. this may be due to the safeClose method defined with serverSocket, but again, I'm not too sure what's up here. This may also be because something failed to execute in one of the try catch statements, causing the thread to never be initialized in the first place.

src/main/java/me/totalfreedom/totalfreedommod/httpd/NanoHTTPD.java

@@ -251,7 +251,8 @@ public abstract class NanoHTTPD
         try
         {
             safeClose(myServerSocket);
-            myThread.join();
+            //This should prevent a null pointer :)
+            if (myThread != null) myThread.join();
         }
         catch (Exception e)
         {