Merge branch 'lilypond/translation'

* lilypond/translation:
  The IR guide
  A better translation for Figured Bass
  Typo
  Tweaking methods
  Voices and Vocals, Fundamental finished
  Explicitly instantiating voices
  Hearing Voices
  Update of Documentation/po/de.po
  Scheme tutorial
  Update macro calls
  Scores and parts reloaded
  Fix Tweaks menu
  Tweaks, naming conventions
  Tweaks, introduction
  Fundamental, finished
  Po update
  Fix menu