If the summary widget is large, it gets a scrollbar. This looks really
weird, so prefer to grow the installer window instead. Discussed with
@sitter and settled on this solution.
ViewSteps can signal the ViewManager that they need more space (in pixels),
which may or may not be honored.
FIXES#778
In order to avoid deep copies, Qt containers over which we iterate must be const
The remaining unported cases require qAsConst (Qt 5.7) or std::as_const (C++17)
