This uses an approach where the axes retain double precision data, and
coordinate with the vtkChartXY and vtkPlotPoints classes to scale the
data appropriately. This required some refactoring of the code dealing
with calculating the bounds and arranging the data ready for being
rendered. Functions that modify the plot transforms required some
enhancement to use the scaling factors when necessary.

Change-Id: Ic084d9dab7f02ded82187bd6207a3f837fef03ec