Derive wxBitmap from wxBitmapBase.

Move code from LoadFile/SaveFile/Create* to
bitmap handlers.
  Implemented wxBitmap::GetSubBitmap.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@19987 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/x11/icon.h

@@ -31,7 +31,7 @@ public:
 
     // For compatibility with wxMSW where desired size is sometimes required to
     // distinguish between multiple icons in a resource.
-    wxIcon( const wxString& filename, int type = wxBITMAP_TYPE_XPM, 
+    wxIcon( const wxString& filename, wxBitmapType type = wxBITMAP_TYPE_XPM, 
             int WXUNUSED(desiredWidth)=-1, int WXUNUSED(desiredHeight)=-1 ) :
         wxBitmap(filename, type)
     {