Part: improve Python interface

+ rename getCurve2dFromGeom2d to makeFromCurve2d
+ add function makeFromCurve and makeFromTrimmedCurve like makeFromSurface
+ implement OffsetCurve.BasisCurve
+ fix memory leak in BRepOffsetAPI_MakePipeShellPy

src/Mod/Part/App/Geometry2d.cpp

@@ -2256,7 +2256,7 @@ PyObject *Geom2dTrimmedCurve::getPyObject(void)
 // ------------------------------------------------------------------
 
 namespace Part {
-std::unique_ptr<Geom2dCurve> getCurve2dFromGeom2d(Handle(Geom2d_Curve) curve)
+std::unique_ptr<Geom2dCurve> makeFromCurve2d(Handle(Geom2d_Curve) curve)
 {
     std::unique_ptr<Geom2dCurve> geo2d;
     if (curve.IsNull())