Each R package should include ../../math/R/Makefile.extension, which also
defines MASTER_SITES. Consequently, it is redundant for the individual
packages to do the same. Package-specific definitions also prevent
redefining MASTER_SITES in a single common place.
Carries out mapping between assorted color spaces including RGB, HSV,
HLS, CIEXYZ, CIELUV, HCL (polar CIELUV), CIELAB and polar
CIELAB. Qualitative, sequential, and diverging color palettes based on
HCL colors are provided along with an interactive palette picker (with
either a Tcl/Tk or a shiny GUI).
