quoted percent repeats

[Dan Eble]

Percent repeats are omitted from cues.  I suggest that the percents should 
appear by default.

Using \addQuote … \unfoldRepeats … is a work around if there are no repeats 
that the user does not want expanded (e.g. voltas).  If there were a way to 
unfold percent repeats selectively, that might be a useful option.  (I remember 
that someone was working on something like that in the past year.)

\version "2.14.2" % the oldest version I tried; still fails in 2.19

top = \repeat percent 2 { c'4 d' e' f' }

\addQuote "q" \top

\new StaffGroup <<
  \new Staff { \top }
  \new Staff {
    s1*0 % create a regular Voice (known \cueDuring issue)
    \cueDuring #"q" #UP { R1*2 }
    g'2 g
  }
>>
— 
Dan