0023934: Compiler warnings in MS VC++ 10

Elimination of compiler warnings
- ExprIntrp: generated file ExprIntrp.tab.c and related WOK scripts removed from the sources
- ExprIntrp, StepFile: added missing declarations and casts; warnings caused by Flex and Bison code suppressed for MSVC compuler by #pragma
- OSD: dummy #includes added to files containing no code for Windows, to avoid warning on empty file
- PLib: piece of code contained in PLib_ChangeDim.gxx included explicitly in cxx and cleaned
- Other places: some casts added to avoid warnings

src/LProp/LProp_CLProps.gxx

@@ -215,6 +215,7 @@ void  LProp_CLProps::Tangent (Dir& D)
 Standard_Real LProp_CLProps::Curvature ()
 {
   Standard_Boolean isDefined = IsTangentDefined();
+  (void)isDefined; // trick to avoid compiler warning on variable unised in Release mode; note that IsTangentDefined() must be called always
   LProp_NotDefined_Raise_if(!isDefined,
           "LProp_CLProps::CurvatureNotDefined()");