Change the default from Lucida Grande to anything else

Usage:

Set the default font with the chart font...
= pie_chart [["Football", 10], ["Basketball", 5]], library: {backgroundColor: "#eee", fontName: "courier new"}

or, set the default font directly...
= pie_chart [["Football", 10], ["Basketball", 5]], {font_family: "courier new", library: {backgroundColor: "#eee"}}