This adds a new helper widget SpVisualizerView to simplify using
visualizers from applications using libsysprof-ui-2 such as
Builder.
We can manage the view range, zoom, etc from this widget going
forward.
This is a major redesign a modernization of Sysprof. The core data
structures and design are largely the same, but it has been ported to
Gtk3 and has lots of additions that should make your profiling experience
smoother. Especially for those that are new to profiling.
There are some very simple help docs added, but we really need the
experts to come in and write some documentation here.
