should we provide an empty stencil?

[Mark Polesky]

Since setting a grob's stencil prop to #f can trigger errors, I
discovered the following workaround. Do we have anything like this
already? If not, shouldn't we? Is there a better way than using an
empty postscript string?

- Mark


#(define-public empty-stencil
   (ly:make-stencil (list 'embedded-ps "") '(0 . 0) '(0 . 0)))

{
  %\override NoteHead #'stencil = ##f
  \override NoteHead #'stencil = #empty-stencil
  c''
}