vtkJSONSceneExporter: optionally write textures and poly LODs
This includes a simple JPEG texture writer that saves the texture inside the .vtkjs file, and a texture LOD series writer that saves the textures as a series of decreasing resolution jpeg files intended to be uploaded to the web. The texture LOD files are saved outside of the .vtkjs file.
If multiple actors use the same texture, the texture will only be written out once.
Edited by Patrick Avery