Added ToBuilder and WeakToBuilder
diff --git a/src/ProtocolBuffers/DynamicMessage.cs b/src/ProtocolBuffers/DynamicMessage.cs
index b740013..4b3a406 100644
--- a/src/ProtocolBuffers/DynamicMessage.cs
+++ b/src/ProtocolBuffers/DynamicMessage.cs
@@ -74,7 +74,6 @@
       Builder builder = CreateBuilder(type);
       Builder dynamicBuilder = builder.MergeFrom(input);
       return dynamicBuilder.BuildParsed();
-
     }
 
     /// <summary>
@@ -247,6 +246,10 @@
       return new Builder(type);
     }
 
+    public override Builder ToBuilder() {
+      return CreateBuilderForType().MergeFrom(this);
+    }
+
     /// <summary>
     /// Verifies that the field is a field of this message.
     /// </summary>