Publish EventAny under its name

[EPashkin]

To generate Widget signals map-event and unmap-event in gtk-rs/gtk#339

[gkoz]

A hack like this just to make two signals automatic feels dubious.

[EPashkin]

Then what we do with 2 problem signals now?

[gkoz]

They can live in the manual widget trait, it's there anyway.

[EPashkin]

So only 2 signals in WidgetSignals :(

[gkoz]

I meant WidgetExtManual because I assume we're getting rid of all *Signal traits.

[EPashkin]

Ok that better that restoring it in signals.rs

[vhdirk]

I just bumped into this when generating subclass traits (gtk-rs/gir#604) for Gtk.Widget. Do you think there'd be any way to do this automatically? I am rather opposed to doing stuff manual for the subclassing traits, since they are all injected into the generated code, and not just reused.
I was thinking of introducing a sort of type alias syntax into the gir config file?