\voiceOne rest positioning

[Urs Liska]

Hi,

I've just updated an example on the German Wikipedia
http://de.wikipedia.org/wiki/Notensatzprogramm#Text

and noticed that the position of the initial \voiceOne rest is suboptimal.
Compare LilyPond's output with that of Score and Amadeus which are both 
better.
I have no clue about the Score input but that of Amadeus is definitely 
default placement.

Of course it is trivial to write a pitched rest here, but I think the 
default placement should be improved. This is also in the context of 
Daniel Spreadbury's recent post about their rest positioning algorithm.

If I write a \voiceOne rest it will be placed that far to the top, even 
if there are only spacer rests in the other voice.
I don't know how that positioning is realized, but I think the rest 
should be placed much lower by default, just with the option to move 
upwards to avoid collisions.

I think that's the current behaviour anyway, so the solution might be 
one of the following:
- place \voiceXXX rest exactly as \oneVoice, just define the direction 
where they move for collision handling.
  (this would also eliminate the problem of having to switch to 
\oneVoice for a single common rest).
- try to determine the pitches before and after the rest and place it in 
the middle (if collision handling allows).

Urs