anchor.diff:  
   Task "PublishNuget" ["NuGet"] <| fun _ ->
       let key =
  -        match getParam "nuget-key" with
  +        match environVarOrNone "nuget-key" with
           | Some(key) -> key
           | None -> getUserPassword "NuGet key: "
   
  
positive.code: // Build steps
  // --------------------------------------------------------------------------------------
  
  // Parameter helpers to be able to get parameters from either command line or environment
  let getParamOrDefault name value = environVarOrDefault name <| getBuildParamOrDefault name value
  
  let getParam name =
      let str = getParamOrDefault name ""
      match str with
          | "" -> None
          | _ -> Some(str)
  
  // Read additional information from the release notes document
  let release =
      let fromFile = LoadReleaseNotes (rootDir </> "Release Notes.md")
  
negative.code:         let appVeyorBuildVersion = int appVeyorBuildVersion
          let nugetVer = sprintf "%s-appveyor%04i" fromFile.NugetVersion appVeyorBuildVersion
          let asmVer = System.Version.Parse(fromFile.AssemblyVersion)
          let asmVer = System.Version(asmVer.Major, asmVer.Minor, asmVer.Build, appVeyorBuildVersion)
          ReleaseNotes.New(asmVer.ToString(), nugetVer, fromFile.Date, fromFile.Notes)
      else
          fromFile
  