Use wx-prefixed macros throughout the repository.

Change {DECLARE,IMPLEMENT}_*CLASS and {DECLARE,BEGIN,END}_EVENT_TABLE
occurrences to use the wx-prefixed version of the macros.

include/wx/imaggif.h

@@ -84,7 +84,7 @@ protected:
 #endif
 
 private:
-    DECLARE_DYNAMIC_CLASS(wxGIFHandler)
+    wxDECLARE_DYNAMIC_CLASS(wxGIFHandler);
 };
 
 #endif // wxUSE_GIF