Lazy focusable widgets

[SamRodri]

Lazy widgets are not fully inited, so if they are focusable they are not visible in the focus tree. This causes problems like in the 'icon' example, where cycle navigation back from the search box only scrolls to the last loaded icon, not the actual last.

Possible solutions:

1 - Create some "focus anchor" thing that exists as a full widget placed at the edges of the lazy bounds, just to receive focus and then remove itself and focus the loaded widget nearest to it.
2- Create custom nav API that Scroll! can use to intercept the navigation-from-edges operations and scroll first before computing.

Workaround:

You can workaround this issue by having a focusable footer of some sort (inside the same Scroll!).