Mapping of AccessibleStateType to AtkStateType

[Niklas Johansson]

Thank you for the answer, somehow I missed the comments in offapi, I 
suppose that I only looked at the comments at api.libreoffice.org... O 
well...

I'll might dig into if OFFSCREEN is the opposite of ATK_STATE_SHOWING 
but I can't really say that I see it as a priority until I find some bug 
that I believe might be related.

Regards,
Niklas