ensure symbols get packaged

Rx.NET/Source/System.Reactive/System.Reactive.csproj

@@ -11,6 +11,7 @@
     <AssemblyOriginatorKeyFile>../ReactiveX.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
     <NoWarn>$(NoWarn);CS1591</NoWarn>
+    <IncludeSymbols>true</IncludeSymbols>
     <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <PackageTags>Rx;Reactive;Extensions;Observable;LINQ;Events</PackageTags>
     <PackageIconUrl>http://go.microsoft.com/fwlink/?LinkId=261274</PackageIconUrl>