Added a MDNS test exec class and did some fixes

test/zutil/net/dns/MulticastDNSClientTest.java

@@ -0,0 +1,17 @@
+package zutil.net.dns;
+
+import java.io.IOException;
+
+/**
+ * Test class for MulticastDNSClient.
+ *
+ * Created by Ziver on 2016-04-26.
+ */
+public class MulticastDNSClientTest {
+
+    public static void main(String[]  args) throws IOException {
+        MulticastDNSClient mdns = new MulticastDNSClient();
+        mdns.start();
+        mdns.sendProbe("apple.local");
+    }
+}