Wrap look-and-feel in a theme

Creates new Theme classes to control the appearance of charts, series, axes and tables.
I think this should be forEach instead of map.  And you also get the index as the second argument in the callback function so I think you could simplify this to:

this.series()
                .forEach(function(series, index) {
                    series.color = d3.functor(self.seriesPalette[index % self.seriesPalette.length]);
                    series.draw(self, dragging);
                });