Splats without stencils (almost)

Alternative to #2264 for fixing #2235  Creates quads for each of ceiling/wall/floor parts of the splat when creating a new node. No more lag! (~120 fps rather than 12)

Some splats don't show up and the x-offset is wrong but I have a feeling the problem is with my maths and not the method.  This seems to be a step in the right direction.