Extends Pie graph type to allow custom series text

Allows the Series label text to be passed to a custom PieLabelFormatter
as a third value, allowing the label text to contain the text, if
desired. (A custom PieLabelFormatter can be created to allow different
formatting of the data, default is percentage)
Build files after pie labels updated (see prev commit)
Merge pull request #1 from OklahomaChristian/pie-labels

Pie labels