ENH:Added Parallel/vtkImageRenderManager Parallel/Testing/Cxx/DistributedDataRenderPass.cxx. Rewrote Parallel/vtkCompositeRGBAPass. Added Allocate*D() and CopyFromFrameBuffer() to Rendering/vtkTextureObject. Removed VTK/Parallel/Testing/Cxx/TransmitImageDataRenderPassOpacity.cxx