anchor.diff:      | Error of string
       | Project of string
       | OutputMode of OutputMode
  +    | CompilerLocation
       | Help
       | Quit
   
  
positive.code:         else
            main state
  
      | Help ->
          match state.OutputMode with
          | Text -> Console.WriteLine(helpText)
  
negative.code:     outputmode {json,text}
        - switches the output format. json offers richer data
          for some commands
      compilerlocation
        - prints the best guess for the location of fsc and fsi
          (or fsharpc and fsharpi on unix)
      "
      
    let outputText = @"
  