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

* 'master' of ssh://jomand@git.sv.gnu.org/srv/git/lilypond:
  Update from Trevor.
  Update from Ralph.
  @unnumberedsubsubsec -> @subsubsection.
  Update from Trevor.
  MusicXML: The dynamics test have been moved to 03a-Directions-MusicXML.xml
  MusicXML: Improve test suite for the direction elements
  MusicXML: Don't try to convert #text as a dynamics tag!
  MusicXML: Better support for dynamics
  Another fix for mpost: $(outdir) is relative.  Also: chain commands with &&.