anchor.diff:          projects |> Seq.iter (runSingleProject)
   )
   
  +//--------------------------------------------------------------------------------
  +// Help 
  +//--------------------------------------------------------------------------------
  +
  +Target "Help" <| fun _ ->
  +    List.iter printfn [
  +      "usage:"
  +      "build [target]"
  +      ""
  +      " Targets for building:"
  +      " * Build      Builds"
  +      " * Nuget      Create and optionally publish nugets packages"
  +      " * RunTests   Runs tests"
  +      " * All        Builds, run tests, creates and optionally publish nuget packages"
  +      ""
  +      " Other Targets"
  +      " * Help       Display this help" 
  +      " * HelpNuget  Display help about creating and pushing nuget packages" 
  +      ""]
  +
  +Target "HelpNuget" <| fun _ ->
  +    List.iter printfn [
  +      "usage: "
  +      "build Nuget [nugetkey=<key> [nugetpublishurl=<url>]] "
  +      "            [symbolskey=<key> symbolspublishurl=<url>] "
  +      "            [nugetprerelease=<prefix>]"
  +      ""
  +      "Arguments for Nuget target:"
  +      "   nugetprerelease=<prefix>   Creates a pre-release package."
  +      "                              The version will be version-prefix<date>"
  +      "                              Example: nugetprerelease=dev =>"
  +      "                                       0.6.3-dev1408191917"
  +      ""
  +      "In order to publish a nuget package, keys must be specified."
  +      "If a key is not specified the nuget packages will only be created on disk"
  +      "After a build you can find them in bin/nuget"
  +      ""
  +      "For pushing nuget packages to nuget.org and symbols to symbolsource.org"
  +      "you need to specify nugetkey=<key>"
  +      "   build Nuget nugetKey=<key for nuget.org>"
  +      ""
  +      "For pushing the ordinary nuget packages to another place than nuget.org specify the url"
  +      "  nugetkey=<key>  nugetpublishurl=<url>  "
  +      ""
  +      "For pushing symbols packages specify:"
  +      "  symbolskey=<key>  symbolspublishurl=<url> "
  +      ""
  +      "Examples:"
  +      "  build Nuget                      Build nuget packages to the bin/nuget folder"
  +      ""
  +      "  build Nuget nugetprerelease=dev  Build pre-release nuget packages"
  +      ""
  +      "  build Nuget nugetkey=123         Build and publish to nuget.org and symbolsource.org"
  +      ""
  +      "  build Nuget nugetprerelease=dev nugetkey=123 nugetpublishurl=http://abc"
  +      "              symbolskey=456 symbolspublishurl=http://xyz"
  +      "                                   Build and publish pre-release nuget packages to http://abc"
  +      "                                   and symbols packages to http://xyz"
  +      ""]
   
   //--------------------------------------------------------------------------------
   //  Target dependencies
   //--------------------------------------------------------------------------------
   
   Target "BuildRelease" DoNothing
  -Target "All" DoNothing
   Target "Nuget" DoNothing
   
   // build dependencies
  
positive.code:     CleanDir outputBinaries
      CleanDir outputNuGet
  
      CleanDirs !! "./**/bin"
      CleanDirs !! "./**/obj"
  )
  
  Target "RestorePackages" (fun _ ->
  
negative.code: "CreateNuget" ==> "PublishNuget" ==> "Nuget"
  
  // all
  Target "All" DoNothing
  "BuildRelease" ==> "All"
  "Nuget" ==> "All"
  
  RunTargetOrDefault "Help"