Changes in the new instruments.xml
Suggesting the following changes:
1. Handbells should use G 8va and F 8va clefs in their grand staff.
2. Marimba could be changed to aPitchRange 45-96 and pPitchRange 36-96.
3. Bass marimba should have pPitchRange 36-53.
4. The xylophone should have a G 8va clef.