release: 1.3.80

release: 1.3.80

===========

* Created Thread_devnull_engraver and Voice_devnull_engraver iso
  single A2_devnull_engraver in Thread context.  It seems however
  that the hack in A2_devnull_engraver works better.

* Coriolan fixes.

* Slur attachment fix for chords where case slurdir != stemdir.

* Made various fixes for (line-)broken slurs.

* Fixed slur_height (), which fixes most ugly slurs (Yeah!).

* Fixed some silly url reversals in FAQ.

* Finished Coriolan music entry (again); entered second viola part.

* Updated Coriolan to use part combiner on Voice level for wind parts
  and on Staff level for violi and bassi.

* Part-combiner now uses duration inquiry, which fixes rhythm-related
  bugs in determining solo/a2.  Also, rests are taken into account.

* Another crude fix for almost unexplainable (with a gdb that dumps
  core on ly_display_scm) all-zero control points slurs.

* Fixed slurs that crossed through stems and note heads.  Note
  that beautifying of ugly slurs is still broken.

* Made crude fixes slurs don't crash, bezier still crashes on
  infinitely steep slurs (eg flauti-part *with* slur_engraver).

1.3.79.