Adding isNotEmpty property to collection and string.

BUG= http://dartbug.com/3074
R=floitsch@google.com

Review URL: https://codereview.chromium.org//15263004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/yaml@23294 260f80e4-7a28-3924-810f-c04153c831b5

pkgs/yaml/lib/src/yaml_map.dart

diff --git a/pkgs/yaml/lib/src/yaml_map.dart b/pkgs/yaml/lib/src/yaml_map.dart
index 29fec75..303d8ed 100644
--- a/pkgs/yaml/lib/src/yaml_map.dart
+++ b/pkgs/yaml/lib/src/yaml_map.dart
@@ -36,6 +36,7 @@
   Iterable get values => _map.values;
   int get length => _map.length;
   bool get isEmpty => _map.isEmpty;
+  bool get isNotEmpty => map.isNotEmpty;
   String toString() => _map.toString();
 
   int get hashCode => hashCodeFor(_map);