AccidentalCautionary in NullVoice

[Dan Eble]

Here is a work-around for 
https://code.google.com/p/lilypond/issues/detail?id=3834 which I suppose 
suggests both a resolution and a reason not to make a distinction between 
Accidental and AccidentalCautionary in the first place.  (I understand there 
are probably good reasons to make a distinction or it wouldn’t be that way.)

\version "2.18.0"

\layout {
  \context {
    \NullVoice
    \omit AccidentalCautionary
  }
}

notes = \relative c' {
  ces?4 c? cis? cisis?
}

\new Staff <<
  \new Voice \notes
  \new NullVoice = "null" \notes
>>
— 
Dan