Updated experimental rhythm library.

Experimental library/rhythm.py now uses BurnishedTaleaRhythmMaker instead of
TaleaRhythmMaker.

TaleaRhythmMaker is effectively deprecated. BurnishedTaleaRhythmMaker does
everything that TaleaRhythmMaker does (and then some). Use
BurnishedTaleaRhythmMaker instead. But note that BurnishedTaleaRhythmMaker will
be renamed to TaleaRhythmMaker soon.
inherits from Burnished