Replace wxList used in wxHtmlPrintout with wxVector<> too

Prefer the use of the standard-like template class to macro-based list.

It also makes more sense to use a vector rather than a linked list here,
as the elements are never removed from or inserted into m_Filters, so
there is no reason to prefer the list structure.

include/wx/html/htmprint.h

@@ -200,7 +200,7 @@ private:
     float m_MarginTop, m_MarginBottom, m_MarginLeft, m_MarginRight, m_MarginSpace;
 
     // list of HTML filters
-    static wxList m_Filters;
+    static wxVector<wxHtmlFilter*> m_Filters;
 
     wxDECLARE_NO_COPY_CLASS(wxHtmlPrintout);
 };