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/imagiff.h

@@ -35,7 +35,7 @@ protected:
     virtual bool DoCanRead(wxInputStream& stream) wxOVERRIDE;
 #endif
 
-    DECLARE_DYNAMIC_CLASS(wxIFFHandler)
+    wxDECLARE_DYNAMIC_CLASS(wxIFFHandler);
 };
 
 #endif // wxUSE_IMAGE && wxUSE_IFF