During app teardown, the Application object may be destroyed before
something else, and so having Application::the() return a reference was
obscuring the truth about its lifetime.
This patch makes the API more honest by returning a pointer. While
this makes call sites look a bit more sketchy, do note that the global
Application pointer only becomes null during app teardown.
Ideally, we would copy the file to `/res/wallpapers`, add an entry to
`ComboBox` model and set the index to this entry. I didn't want to
touch anything outside of `DisplaySettings`, so this is more of a
workaround :^)
Get rid of the weird old signature:
- int StringType::to_int(bool& ok) const
And replace it with sensible new signature:
- Optional<int> StringType::to_int() const
Running 'pape' without arguments (or just editing the WindowServer.ini by hand)
can confuse DisplaySettings. Specifically, if the 'Wallpaper' is set to
'/res/wallpapers/', then DisplaySettings used to crash because 'name_parts'
wouldn't contain any trailing element.
It's hard to define desired behavior, but this is better than crashing
and confusing the user.
