Address build warnings:
audio_clock.cc:911: warning: Empty msgid. It is reserved by GNU gettext:
gettext("") returns the header entry with
meta information, not the empty string.
audio_clock.cc:912: warning: Empty msgid. It is reserved by GNU gettext:
gettext("") returns the header entry with
meta information, not the empty string.
session_dialog.cc:604: warning: Empty msgid. It is reserved by GNU gettext:
gettext("") returns the header entry with
meta information, not the empty string.
session_dialog.cc:605: warning: Empty msgid. It is reserved by GNU gettext:
gettext("") returns the header entry with
meta information, not the empty string.
Use ("") instead of _("") to try to indicate syntactically that
localization markup intentionally has been left out.
When importing a multi-track MIDI files with identical track-names,
Ardour would create the same file for each track. Effectively
overwriting an existing file.
The following MIDI file would create the same file twice
in `interchange/`, once for each MTrk.
```
MFile 1 2 240
MTrk
0 Meta SeqName "Foo Bar"
0 TimeSig 4/4 24 8
0 Tempo 666667
0 Meta TrkEnd
TrkEnd
MTrk
0 Meta TrkName "Foo Bar"
0 On ch=10 n=36 v=95
...
```
During drag-motion callbacks the data to be dragged is n/a.
However we like to discriminate if drop is possible.
When dragging regions, the data-type of the region to be dragged
is unknown, so different `x-ardour/region` targets are not an
option, either.
Until a better option is presented, a static global is used
to set the data-type for region.pbdid drags.
Major changes: do not delete and recreate markers and curves for every tempo map
change, attach tempo curves directly to their (preceding) tempo marker, notable
cleanup of TempoCurve class to remove unnecessary members.
More tweaks expected since algorithm for matching markers and tempo map
points is not correct yet.
