Provide means for invoking inline PS scripts from MSBuild

InvokeScript.tasks

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <!-- USAGE EXAMPLE
  <PropertyGroup>
    <MyScript><![CDATA[
        function Foo()
        {
            $targetFileName = args[0]
            $targetPdbName = args[1]
            $targetPath = args[2]
        }
      ]]>
    </MyScript>
  </PropertyGroup>
  <Target Name="AfterBuild">
    <InvokeScript Script="$(MyScript)" Function="Foo" Parameters="$(TargetFileName);$(TargetName).pdb;$(TargetPath)" />
  </Target>
  -->
  <!-- Based on http://bartdesmet.net/blogs/bart/archive/2008/02/16/invoking-powershell-scripts-from-msbuild.aspx -->
  <UsingTask TaskName="InvokeScript" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll">
    <ParameterGroup>
      <Script ParameterType="Microsoft.Build.Framework.ITaskItem" Required="true" />
      <Function ParameterType="System.String" Required="true" />
      <Parameters ParameterType="Microsoft.Build.Framework.ITaskItem[]" Required="false" />
    </ParameterGroup>
    <Task>
      <Reference Include="System.Management.Automation" />
      <Using Namespace="System.Text" />
      <Using Namespace="System.Management.Automation" />
      <Using Namespace="System.Management.Automation.Runspaces" />
      <Code Type="Fragment" Language="cs">
        <![CDATA[        
            var runspaceConfig = RunspaceConfiguration.Create();

            using (var runspace = RunspaceFactory.CreateRunspace(runspaceConfig))
            {
                runspace.Open();

                var commandLine = new StringBuilder();
                commandLine.Append(Function + " ");

                foreach (var parameter in Parameters)
                {
                    commandLine.AppendFormat("\"{0}\" ", parameter.ItemSpec);
                }

                using (var scriptInvoker = new RunspaceInvoke(runspace))
                {
                    scriptInvoker.Invoke(Script.ItemSpec);
                    scriptInvoker.Invoke(commandLine.ToString());
                }
            }

            return true; 
      ]]>
      </Code>
    </Task>
  </UsingTask>
  
</Project>