0022598: Approximation of p-curve by 2D line

0022598: Approximation of p-curve by 2D line

Check whether p-curve being projected can be approximated by straight line is made before full-scale projection, to improve performance.
If straight, pcurve is created as Line only if this will lead to the same range parameterization as 3d curve, otherwise BSpline of degree 1 is created.
Re-approximation of line pcurves by bsplines removed from ShapeFix_Edge.

Test case updating to new behavior.

Added "static" keyword to the  fixPeriodictyTroubles() function.

Update of test-cases according new behavior

Conflicts:
	tests/de/step_3/D9