Represents one data series for a chart (both data & presentation
information).
Object attributes:
points: List of numbers representing y-values (x-values are not specified
because the Google Chart API expects even x-value spacing).
label: String with the series' label in the legend. The chart will only
have a legend if at least one series has a label. If some series
do not have a label then they will have an empty description in
the legend. This is currently a limitation in the Google Chart
API.
style: A chart-type-specific style object. (LineStyle for LineChart,
BarsStyle for BarChart, etc.)
markers: List of (x, m) tuples where m is a Marker object and x is the
x-axis value to place it at.
The "fill" markers ('r' & 'b') are a little weird because they
aren't a point on a line. For these, you can fake it by
passing slightly weird data (I'd like a better API for them at
some point):
For 'b', you attach the marker to the starting series, and set x
to the index of the ending line. Size is ignored, I think.
For 'r', you can attach to any line, specify the starting
y-value for x and the ending y-value for size. Y, in this case,
is becase 0.0 (bottom) and 1.0 (top).
color: DEPRECATED