Added the ability to use an IEnumerable<T> when adding to a list, so you can do:

new Foo.Builder {
   RepeatedValue = { x.Select(y) }
};

... a bit like LINQ to XML.
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
index fdd4aca..5ee9065 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
@@ -321,7 +321,7 @@
         return this;
       }
       
-      public scg::IList<global::Google.ProtocolBuffers.TestProtos.TestOptimizedForSize> RepeatedMessageList {
+      public pbc::IPopsicleList<global::Google.ProtocolBuffers.TestProtos.TestOptimizedForSize> RepeatedMessageList {
         get { return result.repeatedMessage_; }
       }
       public int RepeatedMessageCount {