Removes the need of using the legacy code in polygon/PolyLine.{h,cpp},
refactoring all CPolyLine instances with SHAPE_POLY_SET instances.
The remaining legacy methods have been ported to SHAPE_POLY_SET;
mainly: Chamfer, Fillet, {,Un}Hatch.
The iteration over the polygon vertices have been simplified using the
family of ITERATOR classes.
* Split and rewrite the preview window and canvas.
* Create a new class for handling the board information.
* Adds new render targets: openGL, legacy, and ray tracing.
* Render targets take full advantage of the new 3D plugins system and 3D cache
for a fast 3D model loading.
* Faster board loading.
* New OpenGL render is faster than the old one.
* New ray tracing render target with a post processing shader.
* Use of new 3D plugins (WRL, X3D, STEP and IGES) and 3D model caching.
* Preview of 3D model while browsing the file name.
* 3D preview of the footprint while adding / align 3D shapes.
* Render of 3D models according to attributes: Normal, Normal+Insert, Virtual.
* Pivot rotation centered in one point over the PCB board.
* Shortcuts keys improved for XYZ orientation..
* Animated camera.
Now all are calculated using the top to bottom draw Y axis. This is perhaps not a good idea, but at least it will be easy to change, later.
Code cleaning relative to these bounding boxes.