Merge branch 'master' of ssh://jomand@git.sv.gnu.org/srv/git/lilypond

* 'master' of ssh://jomand@git.sv.gnu.org/srv/git/lilypond:
  MusicXML: Better title for chordnames example
  MusicXML: No need to keep really long test for percussion staves, use short one
  MusicXML: Fix using lxml as XML parser
  Remove a duplicate definition of system-start-text-interface.
  A few fixes for cross-staff tuplet brackets.
  Thinko: don't follow the beam on a kneed tuplet.
  Small tweak for the alignment of a TrillSpanner.
  Fine-tune alignment for TrillSpanners.
  Fix 553.