Bezier Mesh Surface V0.6

As the Bezier functions are essentially a development tool, I find myself in need of a 'debugger'.

This 'thing' is an update of the Bezier library. The primary additions are a couple of debugging aids. Specifically, the ability to draw the control points as a wireframe, and the ability to do the same with the quad lines that make up the actual surface.

I have also refactored the various files. The maths.scad files contains some additional functions that were useful, including some more