Added ColorFingering to indicatortools. NEW FUNCTIONALITY.

Use for woodwing color variation fingerings.

Produces scaled-down markup of a (positive integer) fingering number surrounded
by a circle.

Example:

    >>> note = Note("c'4")
    >>> fingering = indicatortools.ColorFingering(1)
    >>> attach(fingering, note)
    >>> f(note)
    c'4
            ^ \markup {
                    \scale
                            #'(0.75 . 0.75)
                            \override
                                    #'(circle-padding . 0.25)
                                    \circle
                                            \finger
                                                    1
                    }

See the API entry for more examples.