Provide the safe color set for color blindness,
the simulator of protanopia, deuteranopia.
The color sets are collected from:
Wong, B. (2011) ,
< http://mkweb.bcgsc.ca/biovis2012/>, and
< http://geog.uoregon.edu/datagraphics/color_scales.htm>.
The simulations of the appearance of the colors to color-deficient
viewers were based on algorithms in
Vienot, F., Brettel, H. and Mollon, J.D. (1999)
.
The cvdPlot() function to generate 'ggplot' grobs of simulations
were modified from < https://github.com/clauswilke/colorblindr>.