Update the mDNS command line tools in the mdns package

pkg/mdns/lib/mdns.dart

Index: pkg/mdns/lib/mdns.dart
diff --git a/pkg/mdns/lib/mdns.dart b/pkg/mdns/lib/mdns.dart
index d62c391909add65eaf4d23329b7f3c58f31c1984..2d3e5e8631210fce1718b2d3f3d87bb27d12e51d 100644
--- a/pkg/mdns/lib/mdns.dart
+++ b/pkg/mdns/lib/mdns.dart
@@ -58,12 +58,3 @@ abstract class MDnsClient {
       String name,
       {Duration timeout: const Duration(seconds: 5)});
 }
-
-// Simple standalone test.
-Future main(List<String> args) async {
-  var client = new MDnsClient();
-  await client.start();
-  ResourceRecord resource = await client.lookup(RRType.A, args[0]).first;
-  print(address);
-  client.stop();
-}