* Documentation/user/refman.itely (Automatic note splitting):

* Documentation/user/refman.itely (Automatic note splitting):
remove Thread references.

* input/no-notation/pc-direction.ly: remove file.

* ly/engraver-init.ly: remove Thread

* input/regression/tie-chord-partial.ly: remove file.

* scripts/convert-ly.py (conv): \harmonic rule

* lily/new-fingering-engraver.cc (acknowledge_grob): add new
notation for harmonic notes: <c' g''\harmonic>

* Documentation/user/refman.itely (Percussion staves): update doco.

* ly/engraver-init.ly: add DrumStaff and DrumVoice contexts