[jmsl] Clef change in one staff causes all staves to display clefs

[jmsl at music.columbia.edu]

Hi Nick,

I noticed that when I change a clef in one staff, all other staves  
show their current clefs.  Calling the other staves'  
setDisplayClef(false) method doesn't change this.

Is it possible to update the layout manager to hide non-changing clefs  
in the other staves such that:

- if one clef or more clefs are different, include the extra space  
necessary in the other staves, but don't display the clefs
- if no clefs are different, no extra space and don't display the  
clefs (unless first visible measure rendered)

thanks,
Peter McCulloch