Articulate of short \prall

[Hans Aberg]

The "articulate.ly" file (tried with LilyPond 2.16.0) cannot handle \prall 
applied to a 16th note, as in the example below, which is used in Balkan music. 
In the example below, the first 4th note indicates this use, and the second the 
expansion I would prefer: just ignore moving back to the ornament main note. 
Currently, it squeezes an 8th note in, with the error "programming error: Going 
back in MIDI time".

----

\include "articulate.ly"

music = <<
  \new Staff {
  \tempo 4 = 120
  \time 2/4
    \relative c' {
      d16 c\prall b a  d16 c32 d b16 a |
    }
  }
>>

\score {
  \music
        \layout {}
}

\score {
  \unfoldRepeats \articulate \music
        \midi {}
}

----