Clef transparent does not hide clefOctavation

[Michael Scott Cuthbert]

> I'm not top posting (I don't know what that is!)

the override Clef transparent tag does not get rid of the "8" on octava clefs. 
If there's another way to do it, I haven't seen it and it'd be great to 
document.

Thanks for the amazing work! We've just got MusicXML ossias to Lilypond almost
100% working thanks to the great docs.

Best, Myke Cuthbert (address@hidden)

########### begin snippet #############


\version "2.16.0"

\new Staff  = testStaff
                    \with {
                          \override Clef #'transparent = ##t
                        }
        { \clef "treble_8" c4 }