a "Pythagorean address" notation

This is used to describe notes in terms of a chain of perfect
fifths/fourths, but uses a traditional note name plus one or two numbers
after it, much like an angle is fine-tuned by minutes and seconds.

Format: NN�XX�YY

NN = A note name which may be modified with a sharp or flat.
XX = number of Pythagorean commas (1/53 octave) sharp (plus) or flat (minus)
of the note name.
YY = number of 306-tone commas sharp or flat; decimals are allowed
optionally

So, the note G+0-1 (in the key of C), means 3/2 (701.9550 c) plus no
Pythagorean commas minus one 306-tone comma (-1.7697 c), equalling 700.1853
c, very close to a 12-tet perfect fifth. E-1+1 is another way to express
5/4, being one "schisma" higher than 8192/6561, the Pythagorean diminished
fourth.