Fix ugly code in ClefModifier alignment
Fix bugs with aligning on main part of the NoteColumn

NoteColumns may contain either noteheads or rests, so the function
was changed to handle the case when NoteColumn contains only rest.

ly_scm2bool returns true when the argument is unset - that's not
what we want: unset properties should evaluate to false.
Use aligned-on-x-parent instead of other callbacks for some grobs

Now that we have an easy way of specifying different alignments for
grob and its parent (see 0c4f221e5d), we can use aligned-on-.-parent
in places that we previously used .-aligned-on-self.  With this change,
the users have more control over the placement of grobs.

Affected grobs:
- InstrumentSwitch
- Script
- SostenutoPedal
- SustainPedal
- UnaCordaPedal
Issue 4071: scheme-tutorial.itely: missing closing paren

But it turns out that the "formal" definition of a list given there is
unsuitable for determining the list status of circular lists because the
definition, well, turns out to be circular.
Simplify the NullVoice context

issues 3834 3825 3734
Simplify the NullVoice context, and move it under Score

issues 3834 3825 3734
The Tie_performer and similar give their timing information to
Lyric_performer without any need for Note_performer.
Remove tied accidentals after line-breaking
Doc-ca: Priority II Catalan translation
Doc: CG - Added Ralph Palmer and Federico to Bug Squad

Issue 4080
Issue 4075: Doc: Correct the instrumentTransposition setting in NR 2.1.6

  The value of instrumentTransposition affects the MIDI
  pitch.  As all the notes in this example are entered
  at the correct sounding pitch no instrument transposition
  is required.  Previously Kaspar sounded an octave too low.
Merge branch 'master' of /home/jcharles/GIT/Lily/. into translation
Doc-fr: full update
Release: bump VERSION_DEVEL.
PO: update template.
Release: update news.
Release: bump Welcome versions.
Update release process in CG
LSR updates
Merge remote branch 'origin/release/unstable' into HEAD
Release: bump VERSION.