v8.0

• Rework dulcimer versions to omit tabs for tunes not in 'D'

  The dulcimer tabs correctly represented all the melodies, but playing
  tunes in keys other then 'D' was unsatisfactory because the drone
  strings were out of tune.

  There's no easy fix for this. Pro-tem, this fix removes the tabs from
  the existing Dulcimer tunebook (just leaving the cords), and creates
  a new version with both chords and tabs but just for tunes in 'D'.