Added DivisionMaker to newmusicmakertools.

Object model of a partially evaluated function that accepts duration as
input and returns nonreduced fractions as output.

Follows the two-step configure-once / call-repeatedly pattern established
in rhythmmakertools.

The class is concrete and can be used directly.

Examples:

    >>> maker = newmusicmakertools.DivisionMaker(pattern=[(1, 4)])

    >>> maker(Duration(3, 4))
    [NonreducedFraction(1, 4), NonreducedFraction(1, 4), NonreducedFraction(1, 4)]

    >>> maker(Duration(2, 4))
    [NonreducedFraction(1, 4), NonreducedFraction(1, 4)]

    >>> maker(Duration(5, 8))
    [NonreducedFraction(1, 4), NonreducedFraction(1, 4), NonreducedFraction(1, 8)]

    >>> maker(Duration(0))
    []

More examples included in API entry.