0024023: Revamp the OCCT Handle - gcc and clang

Adaptations for compiling with GCC 4.7 and 4.8:
- Construction semantics is used for Handle objects being initialized by const Handle objects of derived type, to avoid overload resolution error in GCC 4.7.
- Missing includes added.
- Fixed bugs related to misuse of direct casts of handle.
- Eliminate CLang warnings on uninitialized and unused variables, functions, and expressions

src/GeomToStep/GeomToStep_MakeAxis2Placement3d.cxx

@@ -134,6 +134,6 @@ GeomToStep_MakeAxis2Placement3d::GeomToStep_MakeAxis2Placement3d
 const Handle(StepGeom_Axis2Placement3d) &
       GeomToStep_MakeAxis2Placement3d::Value() const
 {
-  StdFail_NotDone_Raise_if(!done == Standard_True,"");
+  StdFail_NotDone_Raise_if(!done,"");
   return theAxis2Placement3d;
 }