Interface fixes and tweaks for Phoenix

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70200 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/scrolbar.h

@@ -240,5 +240,10 @@ public:
         @see GetThumbPosition()
     */
     virtual void SetThumbPosition(int viewStart);
+
+    /**
+       Returns @true for scrollbars that have the vertical style set.
+    */
+    bool IsVertical() const;
 };