Update nuspec so only TinCan stuff included. Realease readme update

Author: samcayford

RELEASE.md

@@ -2,12 +2,22 @@ Make sure that the `TinCan/Properties/AssemblyInfo.cs` has been updated with new
 
     TinCan -> Properties -> Assembly Information
 
-Then set the Build Configuration to "Release" and build the solution. (Verify `bin/Release/TinCan.dll` has correct version.)
+Obtain the `TinCan.NET.pfx` file that is used for signing the relevant portions of the release.
+
+Then right-click the solution in the "Solution Explorer" view and select "Batch Build...". Check the "Build" checkbox for the following `TinCan` configurations:
+Release-net35
+Release-net40
+Release-net45
+Release-net45-signed
+
+The click "Build" to build the selected configurations. (Verify `bin/Release/net<X>/TinCan.dll` has correct version.)
 
 With `nuget.exe` installed and in your path do:
 
     cd TinCan
-    nuget pack TinCan.csproj -sym -Prop Configuration=Release
+    nuget pack TinCan.csproj -sym -Prop Configuration=Release-net35
     nuget push TinCan.(version).nupkg
 
+Note: Providing a `Configuration` property is mandatory, otherwise `nuget` will build the `Debug` configuration and include that in the package. The `<files>` portion of the `.nuspec` ensures all releases built previously are in the created `nuget` package.
+
 Commit the updated assembly information file and push to master. Upload the generated `TinCan.(version).nupkg` as a GitHub tag release.

TinCan/TinCan.nuspec

@@ -19,6 +19,6 @@
     </dependencies>
   </metadata>
   <files>
-      <file src="bin\Release\**" target="lib" />
+      <file src="bin\Release\**\TinCan*" target="lib" />
   </files>
 </package>