Add control for details of the difference plots to the configuration file
Request from Michael Walters at NOAA:
"FYI, some members of our group would like to be able to customize the range and color palette for the difference plots. That doesn't appear to be possible right now, because the colorMap and dataRanges options aren't passed along to the mappedPlottingFunction (line 424 of plotcreatefns.py)."
Note from Eva:
Those range and color options are specifically meant to apply to the main data plots. Instead of repurposing them, We should find a way to add control of the difference plot settings specifically.