mark sugestion

[César Penagos]

Hi All:
Working in a Mozart Flute and Harp Concerto, I found a turn mark during the 
flute part.  The \turn mark seems have to be placed in the middle of to 
notes.  This is logical becouse, turn afects two notes not only one note.  
Lylipond put the \turn over the note where it is wirtten.  My sugestion if is 
posible is to make the \turn mark be positioned in the middle of the concernig 
notes. As you can find in the Breitkopf & Härtel (from complete works edition 
1877-1883).