Reorganize mdv and observe packages

pkg/observe/test/list_change_test.dart

 // Copyright (c) 2013, the Dart 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 file.
 
-import 'package:mdv_observe/mdv_observe.dart';
+import 'package:observe/observe.dart';
 import 'package:unittest/unittest.dart';
 import 'utils.dart';
 
 // This file contains code ported from:
 // https://github.com/rafaelw/ChangeSummary/blob/master/tests/test.js
 
 main() {
   // TODO(jmesserly): rename this? Is summarizeListChanges coming back?
   group('summarizeListChanges', listChangeTests);
 }
@@ skipping 265 matching lines @@
       model.insert(0, 5);
       model[2] = 6;
       model.add(7);
       assertEditDistance(model, 4);
     });
   });
 }
 
 _delta(i, r, a) => new ListChangeRecord(i, removedCount: r, addedCount: a);
 _filter(records) => records.where((r) => r is ListChangeRecord).toList();