anchor.diff:  
       seq {
           yield! includeFile true assembly
  -        yield! includeFile false <| Path.ChangeExtension(assembly, "pdb")
  -        yield! includeFile false <| Path.ChangeExtension(assembly, "xml")
  +        yield! includeFile reqXml <| Path.ChangeExtension(assembly, "xml")
  +        yield! includeFile true <| Path.ChangeExtension(assembly, "pdb")
           yield! includeFile false <| assembly + ".config"
       }
   
  
positive.code:             Publish = hasBuildParam "nugetkey" 
              Files =
                  [
                      yield! addAssembly @"lib\net45" @"..\bin\MBrace.Streams.dll"
                  ]
          })
          ("nuget/MBrace.nuspec")
  
negative.code:     if File.Exists (Path.Combine("nuget", file)) then (file, Some target, None)
      else raise <| new FileNotFoundException(file)
  
  let addAssembly reqXml (target : string) assembly =
      let includeFile force file =
          let file = file
          if File.Exists (Path.Combine("nuget", file)) then [(file, Some target, None)]
  