Split off the Serialization namespace into a new assembly.
diff --git a/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj b/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
index 5e31987..bf22426 100644
--- a/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
+++ b/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
@@ -124,6 +124,10 @@
     <Compile Include="WireFormatTest.cs" />

   </ItemGroup>

   <ItemGroup>

+    <ProjectReference Include="..\ProtocolBuffers.Serialization\ProtocolBuffers.Serialization.csproj">

+      <Project>{231391AF-449C-4a39-986C-AD7F270F4750}</Project>

+      <Name>ProtocolBuffers.Serialization</Name>

+    </ProjectReference>

     <ProjectReference Include="..\ProtocolBuffers\ProtocolBuffers.csproj">

       <Project>{6908BDCE-D925-43F3-94AC-A531E6DF2591}</Project>

       <Name>ProtocolBuffers</Name>