Accidentals algorithm

[Hans Aberg]

I made an algorithm that computes accidentals on the algebraic level:  
the notes of the scales of staff and music are defined by linear  
combinations from a set of formal seconds. The typesetting is  
independent of the tuning system: the pitches are found by plugging  
values into these seconds, which can be done when writing an audio  
file. There is another algorithm for doing that.

The idea is to allow for very general types of scales and music. The  
staff scale does not need to be the traditional minor scale, have  
seven notes per diapason, or even defined by just a minor and a major  
second.

There Haskell code is available, in case somebody wants to check if it  
might be useful for LilyPond.

  Hans