add more pure virtuals to wxBrushBase; fix the GetColour() functions to return a wxColour object and not a reference; remove from docs the non-existent SetColour(const wxString&) overloads

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@52901 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/os2/brush.h

@@ -36,7 +36,7 @@ public:
     virtual void SetStipple(const wxBitmap& rStipple);
 
     wxColour GetColour(void) const;
-    virtual wxBrushStyle GetStyle(void) const;
+    wxBrushStyle GetStyle(void) const;
     wxBitmap* GetStipple(void) const;
     int       GetPS(void) const;