0030582: Coding - avoid defining references to properties of NULL objects

Approx_SweepApproximation::Perform() now creates empty arrays.
GeomAdaptor_SurfaceOfRevolution::UTrim() - fixed No_Exception misuse.
StdPrs_ShadedShape - fixed defining an invalid reference to Poly_Triangulation::UVNodes().

BSplCLib::MovePoint() and BSplCLib::MovePointAndTangent() now take optional
weights parameter as pointer consistent to other methods like BSplCLib::BuildEval().

src/NCollection/NCollection_DefineHArray1.hxx

@@ -29,6 +29,7 @@ class HClassName : public _Array1Type_, public Standard_Transient {
  public:                                                                       \
    DEFINE_STANDARD_ALLOC                                                       \
    DEFINE_NCOLLECTION_ALLOC                                                    \
+   HClassName () : _Array1Type_ () {}                                          \
    HClassName (const Standard_Integer theLower,                                \
                const Standard_Integer theUpper) :                              \
      _Array1Type_ (theLower,theUpper)  {}                                      \