Add more staff - for choral conductors

[matissbr]

Hey!

Absolutely love this. I am choral conductor and when learning new pieces it is very nice to play around with sightreader for a while and then move on to serious stuff.

Can you add more staffs? Like separately Sopr Alt Tenor Bass. For now there is only Grand staff. But choral conductors are using usually 4 and more.

kind regards
Matiss

[versilov]

This should be relatively easy. I made a pull request for electric bass staff — which is played an octave lower than grand bass staff.
If it's approved I can add other staves for you.