Couple warning fixes (#139)

* Use -Wno-tautological-constant-out-of-range-compare for Clang (these warnings come from the sanity checks in generated IfcXXX files).

* Remove unused variable and typedefs + suppress uint->bool conversion warnings (MSVC) + add note about Clang in README

* MSVC uint->bool convesion warning fixes when IFC4 is defined

src/examples/IfcAdvancedHouse.cpp

@@ -52,12 +52,6 @@
 #include <vld.h>
 #endif
 
-// Some convenience typedefs and definitions. 
-typedef std::string S;
-typedef IfcParse::IfcGlobalId guid;
-typedef std::pair<double, double> XY;
-boost::none_t const null = boost::none;
-
 // The creation of Nurbs-surface for the IfcSite mesh, to be implemented lateron
 void createGroundShape(TopoDS_Shape& shape);