Accidental style in presence of mid-bar line breaks.

[Richard Shann]

In 18th c. mss and prints it is quite common to create line breaks
during bars - I've found this much improves the legibility of some
florid slow movements.

However, it seems that the available accidental styles only take
account of barlines and ignore line breaks, which is not very
practical, since the brain, seeing a start of line with key signature
and a note following without any accidental, will naturally play the
note according to the key signature, not holding over any accidental
from earlier in the bar on the previous line.

I don't know if this is covered in Gould, but it would be nice if
LilyPond could handle this.

Richard