Removed ggplot2 build-time dependencies (Reported by @thomasp85, #21)
Fixed bug in stat_hdr_lines_fun() which drew lines
between components of disconnected HDRs (Reported by @afranks86, #20)
Added geom/stat_hdr_rug() for
visualizing marginal HDRs via “rug plot” style graphics along plot axes
(#14)
Added geom/stat_hdr_points() and
geom/stat_hdr_points_fun() for visualizing HDR
membership of points via a colored scatterplot (#15)
level to probs