Add support for nightingale graphs. This type of plot is like pie chart but
with stacking of values for each piece plus individual size of each piece.
Example:
https://upload.wikimedia.org/wikipedia/commons/1/17/Nightingale-mortality.jpg.
Original issue reported on code.google.com by mike.lischke on 10 Aug 2013 at 2:48
Original issue reported on code.google.com by
mike.lischke
on 10 Aug 2013 at 2:48