* Added color options to hdr.boxplot.2d().
* Modified hdr(), hdr.boxplot() and hdr.den() to allow a Box-Cox transformation to be used when computing the density. This allows the density estimate to be non-zero only on the positive real line.
* Bug fix in hdr.boxplot.2d(). It would sometimes plot outliers on a separate plot.
* New argument to hdr.boxplot.2d() to allow the density to be estimated using the kde() function from the ks package.