tied notes in chords

[John Sankey]

Just to note that it is standard harpsichord technique to repeat only
one note (frequently a middle one) when chords are tied across a
stress point such as a bar, to keep the sound of the chord going.
Scarlatti often notes it.

Currently, Lily (1.2.16 anyway) ties all notes of such chords when
any of them are tied, and the output can get really mucked up by
splitting dense chords into multiple voices. It would help if ties
were put only on notes where ties are marked in the code.

John