Preserve alignment between notes and control points when doing an internal
copy/paste of both.
Relative alignment between points on multi-paste is still not preserved. Both
behaviours here are actually useful, perhaps a modifier...
Perhaps debatable if contents should be edited when not in internal mode
whatsoever, but consistent with audio region gain and track automation. It's
less of a problem with the draw tool than, say, object since drawing stuff is
its entire purpose.
When entered, the keyboard is grabbed when the selection becomes non-empty, and
ungrabbed if it becomes empty again or the region is left or the user switches
out of internal mode.
This fixes scroll in internal mode and note moving with arrow keys. Also frees
up useful keybindings when there is no note selection, which is much nicer than
the "nothing works in edit mode at all" greedy grab approach used previously.
Attempt #874327892 of getting this damned grabbing right.
This doesn't seem to have been touched for years, and I don't see how such an
obvious bug could possibly have been around for so long, but, well, this fixes
it as far as I can tell.
I am not sure what causes this, but it can happen when finishing a record
sometimes. Probably MidiSource::_writing isn't updated in the right order with
whatever triggers the redisplay, but at least not crashing is better...
For things like copying from pitch bender to a CC.
Also things like fader to pan, but that seems a bit funny. The conversion
probably needs to be a bit smarter here, perhaps taking the normal into
consideration...
Also push the increasingly unwieldly paste parameters into a context object.
As with othe things, currently it is only possible to do "cross-type paste" by
explicitly selecting the target track. We will need to get automation region
view selection working to do better here, but at least for now it's possible to
get the data over.
