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/IGESData/IGESData_FileProtocol.cxx

@@ -41,7 +41,7 @@ IGESData_FileProtocol::IGESData_FileProtocol ()    {  }
   (const Standard_Integer num) const
 {
   Handle(IGESData_Protocol) res;
-  if (num == 1) return theresource;
+  if (num == 1) return Handle(Interface_Protocol) (theresource);
   else if (!thenext.IsNull()) return thenext->Resource(num-1);
   return res;  // Null
 }