Add mDNS discovery to the Fletch compiler

pkg/fletchc/lib/src/verbs/actions.dart

 // Copyright (c) 2015, the Fletch project authors. Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE.md file.
 
 library fletchc.verbs.verbs;
 
 import 'infrastructure.dart' show
     AnalyzedSentence,
     Future,
     TargetKind,
     VerbContext;
 
 import 'attach_verb.dart' show
     attachAction;
 
 import 'compile_verb.dart' show
     compileAction;
 
 import 'create_verb.dart' show
     createAction;
 
 import 'debug_verb.dart' show
     debugAction;
 
+import 'x_discover_verb.dart' show
+    discoverAction;
+
 import 'export_verb.dart' show
     exportAction;
 
 import 'help_verb.dart' show
     helpAction;
 
 import 'run_verb.dart' show
     runAction;
 
 import 'shutdown_verb.dart' show
@@ skipping 75 matching lines @@
   "export": exportAction,
 };
 
 /// Uncommon verbs aren't displayed in the normal help screen.
 ///
 /// These verbs are displayed when running `fletch help all`.
 const Map<String, Action> uncommonActions = const <String, Action>{
   "compile": compileAction,
   "create": createAction,
   "debug": debugAction,
+  "x-discover": discoverAction,
   "shutdown": shutdownAction,
   "x-end": endAction,
   "x-servicec": servicecAction,
   "x-upgrade": upgradeAction,
   "quit": quitAction,
   "show": showAction,
 };