This hopefully fixes an odd macOS specific focus issue.
It also moves the dialog to the popup position when
showing the same dialog using the editor-mixer and later
a detached mixer.
the rest from `tools/convert_boost.sh`.
* replace boost::function, boost::bind with std::function and std::bind.
This required some manual fixes, notably std::placeholders,
some static_casts<>, and boost::function::clear -> = {}.
This removes ::add_grouped_tracks() from Editor selection and
RouteProcessorSelection, since adding grouped stripables is now
a CoreSelection function, and should not be attempted by UI-side
elements
This is mostly a simple lexical search+replace but the absence of operator< for
std::weak_ptr<T> leads to some complications, particularly with Evoral::Sequence
and ExportPortChannel.
The rec-arm circle diameter is given by 0.5 * min (width, height).
For mono tracks the diameter is limited with the height of the
track. When more channel meters are visible the height increases and
the rec-arm circle grows.
The solution here is to constrain the rec-arm button width to its
minimum and not grow to have the same width as other buttons.
This also changes the default meter-height so mono and stereo tracks
have the same height (with default scaling).
