Remove unnecessary heap allocations in wxHtmlDCRenderer

Make m_Parser and m_FS simple objects instead of pointers as it's
completely unnecessary to allocate them on the heap here.

Note that both wxHtmlWinParser (by explicitly including its header) and
wxFileSystem (which is implicitly included via wx/html/htmlpars.h) are
fully declared in the header, so using pointers doesn't even help with
reducing compilation dependencies.

No real changes.

include/wx/html/htmprint.h

@@ -87,8 +87,8 @@ private:
     void DoSetHtmlCell(wxHtmlContainerCell* cell);
 
     wxDC *m_DC;
-    wxHtmlWinParser *m_Parser;
-    wxFileSystem *m_FS;
+    wxFileSystem m_FS;
+    wxHtmlWinParser m_Parser;
     wxHtmlContainerCell *m_Cells;
     int m_Width, m_Height;
     bool m_ownsCells;