Feature Request: ability to position a clef arbitrarily

[ericjs]

A treble clef is a G clef positioned so as to place the G4 on the second line of the staff (as located by the center of the loop at the bottom of the staff). While not often used any more, technically it can be positioned anywhere to make a different line (or space) to be where G4 is located on the staff (e.g. a "french violin clef" places the G4 on the first line). Something similar applies to the other clefs (F3 of the bass clef, etc.).

It would be nice to be able to set up a clef in any position when wanted to enter some historical score, for example Bach's autograph of BWV 995, where the G clef puts the G on the second space.