Volta brackets should export to all parts
Steps to reproduce bug
1. Open or create a score
2. From the lines palette, drag a volta bracket onto the topmost staff of the score
3. File > Parts...
4. Create a part for any staff (other than the topmost staff)
Expected behavior: The volta bracket should appear in the new part
Actual behavior: The volta bracket does not appear in the parts (other than
Discussion: In an orchestra score the volta brackets are not usually placed on every staff. By convention they often appear on the top of each instrument family (such as strings or winds). When extracting a part and deciding whether a part needs a volta bracket it needs look beyond its own staff and iterate through each of the instruments staves above the extracted measure.
MuseScore version: 1.1 (unable to test trunk due to crashes)
(Operating System: Windows 7)