Named palettes
-  The current palette can be saved to a named colormap for future use.
 See set colormap.
-  pm3d and image plots can specify a previously saved palette by name.
 This permits the use of multiple palettes in a single plot command. See colorspec palette.
-  Named palette colormaps can be manipulated as arrays of 32-bit ARGB
 color values. This permits addition of alpha-channel values or other modifications not easily specified in a set palette command.
-  There is a new predefined color scheme set palette viridis.
-  Palettes read from a file or datablock (set palette file) may be specified
 either using fractional color components or 24-bit packed RGB values.
 
