Changed plot.sNPLS functions from base to ggplot2. Most arguments of the functions have been mantained, so this should not produce a major break in compatibility with code from previous versions.

Added unfolded X (Xd) to the output of sNPLS

Added more options for the function plot.sNPLS()

Fixed URLs to canonical form

Fixed https URLS

Fixed bug in cv_snpls when length(dim(Y)) == 1