Add a first layer to shape_3dedge.
Find all layers.  Render layer 0 only using proper interpretation of edgeStepsBack.
Edge detect all layers.  Still only actually rendering layer 0.
Render all layers.  No real improvement on gappiness for now, I need to test things, but the code is working, and hopefully with this plus layer colouring we should be good...
Disable layers by default while I work on them (like this I can feel happy pushing this stuff to github :) )
Fix silly mistake that only now gave an error from the shader compiler (who knows).
Update READMEs with Optimus messing-around.