Large rework of BEZIER_POLY

Add direct handling of quadratic beziers to save compute time and number
of points.  Update cubic interpolation to reduce number of points
generated for a given smoothness

Cache data on open and used cached data to avoid multiple re-calcs

Remove minimum line length and number of segments and replace with
standard max error level.  Allows us to specify the tolerance of bezier
interpolation

common/plotters/plotter.cpp

@@ -244,7 +244,7 @@ void PLOTTER::BezierCurve( const VECTOR2I& aStart, const VECTOR2I& aControl1,
     BEZIER_POLY bezier_converter( ctrlPoints );
 
     std::vector<VECTOR2I> approxPoints;
-    bezier_converter.GetPoly( approxPoints, minSegLen );
+    bezier_converter.GetPoly( approxPoints, aTolerance );
 
     SetCurrentLineWidth( aLineThickness );
     MoveTo( aStart );