First pass at implementation and testing of reusable builders.
diff --git a/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj b/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
index 95ab0b9..b1a7e55 100644
--- a/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
+++ b/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
@@ -105,6 +105,7 @@
     <Compile Include="NameHelpersTest.cs" />

     <Compile Include="Properties\AssemblyInfo.cs" />

     <Compile Include="ReflectionTester.cs" />

+    <Compile Include="ReusableBuilderTest.cs" />

     <Compile Include="ServiceTest.cs" />

     <Compile Include="TestProtos\UnitTestCSharpOptionsProtoFile.cs" />

     <Compile Include="TestProtos\UnitTestCustomOptionsProtoFile.cs" />