Cospectral plot

[ceholden]

Add cospectral plot to available plots.

Some guidelines:

• Interpret bands on "Axis 1" and "Axis 2" as the X and Y axes for the cospectral plot.
• Symbology shows color ~ DOY of observation since it's so interesting
• Control over what years of data are plotted should be accomplished via the date range sliders
• When plotting data from different series against one another, there will most likely be a mismatch of observations. Aggregate data on 2nd axis to data on 1st axis by mean/median within some window of time (e.g., data from MODIS are matched with Landsat observation on March 1st by averaging all MODIS observations between March 1st +/- 1 week)