anchor.diff:        /// extensions to use during the test run.
         /// The value must be in the form '[Namespace.]Type,Assembly[;Parameters]'
         RunnerExtensions: string list // use type + parameters instead of descriptor as string?
  -      Assemblies: string seq
         HintDirectories: string seq
         PluginDirectories: string seq 
         ApplicationBaseDirectory: DirectoryInfo
  
positive.code:       Verbosity = Verbosity.Normal
        RunnerType = null
        RunnerExtensions = []
        Assemblies = [] 
        HintDirectories = [] 
        PluginDirectories = []
        ApplicationBaseDirectory = null
  
negative.code:     param.PluginDirectories |> Seq.iter rtSetup.AddPluginDirectory
      rtSetup
  
  let Run (setParam: GallioParams -> GallioParams) assemblies =
      let param = setParam GallioDefaults
      let package = createPackage param
      let project = createProject param package
  