* undo is not (currently) a Global action, it's an Editor action
* ... but we want the ability to undo a recording
One option would be to chagne Undo to a Global action, which would have a
sizable impact on code and existing shortcuts.
Instead I'm choosing to implement a Rec-page-specific Undo action & shortcut
It's conceivable that someday we would want the Recorder page to ONLY undo
record operations, and the Mixer page to ONLY undo mixer operations, or
something like that. This lays the foundation for that.
This fixes a crash when deleting routes, while there are still
automation events queued for the route.
Specifically, SoloControl has a reference Soloable& _soloable; which
points to the parent route. A rt-event can still hold a valid shared
pointer to the SoloControl, even if the route is destroyed.
Calling SoloControl::actually_set_value is fine (the control still
exists due to the shared ptr), but then checking the parent route:
```
if (_soloable.is_safe() || !can_solo())
```
accesses the already deleted route, which causes a crash.
The solution implemented here is to not bind a shared_ptr to the
realtime event. However, since deletion of the route happens in the main
UI thread, there may or may not still be a race.
In practice, this mostly means integers when presets leave off the ".0", but we
implement all the numeric types here for good measure.
Also while we're at it, warn about unknown types now so it doesn't take three
people a half an hour to figure out what's going on the next time something
like this happens.
This disables the feature added in 057fd9259e.
The idea was to use double-click to reset the fader (like
Harrison consoles). Simply re-select can lead to accidents.
