The user should be required to explicitly enable the taskbar icon on Unix,
it shouldn't be on by default.
- @beginEventTable{wxTaskBarIconEvent}
+ @beginEventEmissionTable{wxTaskBarIconEvent}
Note that not all ports are required to send these events and so it's better
to override wxTaskBarIcon::CreatePopupMenu() if all that the application does
is that it shows a popup menu in reaction to mouse click.