Roll Observatory packages and add a roll script

packages/observe/lib/src/to_observable.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.
 
 library observe.src.to_observable;
 
 import 'package:observe/observe.dart';
 
 /// Converts the [Iterable] or [Map] to an [ObservableList] or [ObservableMap],
 /// respectively. This is a convenience function to make it easier to convert
@@ skipping 27 matching lines @@
     value.forEach((k, v) {
       result[_toObservableDeep(k)] = _toObservableDeep(v);
     });
     return result;
   }
   if (value is Iterable) {
     return new ObservableList.from(value.map(_toObservableDeep));
   }
   return value;
 }