title: Check if enum is in one of desired states
body: <p>If I have enum</p>
  
  <pre><code>    [Flags]
      public enum GameFlow
      {
          Normal = 1,
          NormalNoMove = 2,
          Paused = 4,
          Battle = 8
      }
  </code></pre>
  
  <p>Is it possible to check if the enum is in either one of desired states with a single check? For example if I'd like to check if enum's is either Normal or NormalNoMove do I always have to write it like this?</p>
  
  <pre><code>if(Flow == GameFlow.Normal || Flow == GameFlow.NormalNoMove)
  </code></pre>
  
  <p>It's not a big problem if there are only two values but there will be more enum states and it would be nice if I only would have to change it in one place. Is it somehow possible to make an enum alias that would return true if enum value is either Normal or NormalNoMove? Or do I have to write some kind of helper method to achive that(extension method?)</p>