Bug fix

- The sku attribute is optional. So for the simplicity let's not have
  it.
- When the supportedRuntime element is specified, it trumps what's in
  the executable, so v2.0 needs to be explicitly given.
- Version check is exact check, so "v2.0" and "v2.0.50727" aren't the
  same thing. So we really need to say "v2.0.50727" to let this match
  with .NET 2.0 runtime.

README.markdown

@@ -124,7 +124,8 @@ One way to deal with this is to ensure that .NET 2.0 runtime is installed throug
 
     <configuration>
       <startup>
-        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
+        <supportedRuntime version="v2.0.50727" />
+        <supportedRuntime version="v4.0" />
       </startup>
     </configuration>