resetting state when my page is pop()-ed

[kde at privat.broulik.de]

Hi,

in the apps I wrote I have a onBackRequested signal on my Page class 
which can also be used to reject the back button event (eg. 
event.accepted = false); I think something like this could be added to 
Plasma Mobile Components, too.

Perhaps also a keepStateOnPop (or so) property which defaults to true 
which can be used to disable "going forward" again, though we don't want 
to encourage preventing that, I guess.

Cheers,
Kai Uwe