anchor.diff:  "Clean"
     =?> ("BuildVersion", isAppVeyorBuild)
     ==> "AssemblyInfo"
  -  ==> "VsixManifest"
  +  =?> ("VsixManifest", isAppVeyorBuild)
     ==> "Build"
     ==> "BuildTests"
     ==> "UnitTests"
  
positive.code: 
  let isAppVeyorBuild = environVar "APPVEYOR" <> null
  let buildVersion = sprintf "%s-a%s" release.NugetVersion (DateTime.UtcNow.ToString "yyMMddHHmm")
  let version = sprintf "%s.%s" release.AssemblyVersion (if isAppVeyorBuild then AppVeyor.AppVeyorEnvironment.BuildNumber else "0")
  
  Target "BuildVersion" (fun _ ->
      Shell.Exec("appveyor", sprintf "UpdateBuild -Version \"%s\"" buildVersion) |> ignore
  
negative.code: )
  
  Target "VsixManifest" (fun _ ->
      let version = sprintf "%s.%s" release.AssemblyVersion AppVeyor.AppVeyorEnvironment.BuildNumber
      let manifest = "./src/FSharpVSPowerTools/source.extension.vsixmanifest"
      let doc = new XmlDocument(PreserveWhitespace=true) in
      doc.Load manifest
  