wxSL_INVERSE for MSW. Heavily modified patch 1096922.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@31912 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/slider95.h

@@ -99,6 +99,9 @@ protected:
     // format an integer value as string
     static wxString Format(int n) { return wxString::Format(_T("%d"), n); }
 
+	// Common processing to invert slider values based on wxSL_INVERSE 
+    int MSWInvertOrNot(int value) const; 
+
     // get the boundig box for the slider and possible labels
     wxRect GetBoundingBox() const;