minor cleaning
minor changes
Huge API change.  Meshes are now created before scenes, and scenes now require a list of meshes as the input.  This simplifies everything and creates a bottom-to-top common framework philosophy between windows, scenes, and experiments.
added testShader3.py for testing and demonstrating the new api
Removed Mesh.show() and Mesh.hide() methods.  Now, exp.hide)= and show() directly changes Mesh.visible, which is a much simpler way of doing this.
simplified material import and removed a bug in the process.
minor cleaning
updated QTmonkey3.py to reflect API changes.
massive deleting of old scripts, especially now that much of backwards compatibility is gone.