Live update for sketcher and others

Right now the Line and the Rectangle update nicely (even much better than the old implementation) as they are drawn using OpenCascade instead System.Drawing. Ellipse is done in the same way but it is still a bit unstable.

The PartModeller (3D modelling component of Naro) starts to be separated in Action3D classes. For now only the simple actions (like zoom, rotate, top view) are moved to Action3D class. The Extrude, Cut and Fillet are pretty hardcoded right now, but there are preparations for them to be moved to Action3D items.

PartModeller code will not decrease so much as moving to Action3D classes, because for now its code has a lot of logic that is more than PartModelling code (like update the visualization of the OCAF tree, in fact there are 2 Windows.Forms trees that are updated here: one for a user's eye, in a pretty form, and one in very a detailed way, for the developer). Very probably the future refactor will move this code out of the PartModelling controller code, because it's mostly a view code. (MVC pattern).

What would be next?
- Make ellipse work (and remove other bugs which are found)
- Make extrude work live as action, it will apply without creating again the extruded shape
- Make other actions to work in a live way
- Any other suggestions?