out any inputs displays the options for colormaps. 
% 
% |cmap = crameri('ColormapName')| returns a 256x3 colormap. For a visual
% depiction of valid colormap names, type |crameri|. 
%
% |cmap = crameri('-ColormapName')| a minus sign preceeding any |ColormapName| flips the
% order of the colormap. 
%
% |cmap = crameri(...,NLevels)| specifies a number of levels in the colormap. Default
% value is |256|. 
%
% |cmap = crameri(...,'pivot',PivotValue)| centers a diverging colormap such that white 
% corresponds 