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/TopoShapeFacePyImp.cpp

@@ -713,7 +713,7 @@ PyObject* TopoShapeFacePy::curveOnSurface(PyObject *args)
 
         Standard_Real first, last;
         Handle(Geom2d_Curve) curve = BRep_Tool::CurveOnSurface(edge, face, first, last);
-        std::unique_ptr<Part::Geom2dCurve> geo2d = getCurve2dFromGeom2d(curve);
+        std::unique_ptr<Part::Geom2dCurve> geo2d = makeFromCurve2d(curve);
         if (!geo2d)
             Py_Return;