fixed reidx.cut to correctly handle missing values in sequence (not that that should ever happen in a proper cut)

small fixes to read.tree, %&%, between, init.hue.range.plot, hue.range.lines, plot.tree.ranges,  dendwith.cuts

new: show.sub.tables

between() and lines in plot.tree.ranges() (formerly show.tree.ranges()), with slight extension of hue.range.color() to ease the implementation

derived all from tree data