Fixes bug #6214.
It would be better to do this while dragging, but this would require rewriting
much of the drag code to keep track of a cumulative y delta since the current
position of points would be "sticky" and prevent any movement at all, so this
will have to do for now.
Fix several other cases where a single mouse click could cause several
(not nested) selection ops.
Fix missing selection memento for midi notes and midi commands.
Rename some variables.
Fix random style issues.
combines selection related editor properties with the current editor selection.
The related editor properties are:
mouse mode,
zoom setting,
left frame of the canvas,
y origin of the canvas.
Selection state now includes region views (storing the underlying region id)
and time.
This patch also fixes a region mute undo bug.
This probably isn't correct in several ways, but it works more than it did, so
I figure it's push worthy.
Still not working:
* Saving mute automation list
* Dragged control points are not snapped to model restrictions
(boolean, in this case, but general problem)
* Line goes funny if you record mute automation
(as opposed to drawing it which works)
Two issues:
1) AutomationRegionView not receiving events (CC breakage).
2) Entered values must be rounded to integer for MIDI controllers. This should
be done more generically with ParameterDescriptor for all controls (also
supporting boolean toggles and such), once ParameterDescriptor becomes more
pervasive and takes over Evoral::Parameter, but this will do for now.
Show fancy values on generic GUI controls, automation lane controls, and automation lane verbose cursor.
Fix text display of midiNote values.
Make bigstep of midiNote parameters 12 (one octave).
Add ARDOUR::value_as_string() as a stateless one-stop-shop for value printing.
Remove Canvas::Layout, use Canvas::Container for the same purpose, move child-rendering into Item::render_children() so that it
could theoretically be used by any derived type.
Constrain control points to one per tick (1/1920 beats).
Prior to this it was possible to set two values to the
same time (interpolation and iteration failed).
