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/StepFile/step.yacc

@@ -54,6 +54,12 @@
 #define alloca malloc
 #endif
 
+
+// disable MSVC warnings in flex code
+#ifdef _MSC_VER
+#pragma warning(disable:4244 4131)
+#endif
+
 %}
 %%
 /*  N.B. : les commentaires sont filtres par LEX  */