PROGRAM:        draw_tree
DESCRIPTION:    Produces a simple postscript rendering of a tree.
USAGE:          draw_tree [-dbvs] <tree.nh>|<tree.mod>

OPTIONS:
    <tree_fname>    (Required) File name of tree (expected to be in 
                    Newick format, unless filename ends with '.mod', in
                    which case expected to be a tree model file).
    -d              Print "diagonal" branches, instead of "right-angle" or 
                    "square" ones (produces a "cladogram", as opposed to a 
                    "phenogram").  This option implies -s.
    -b              Suppress branch lengths.
    -v              Vertical layout.
    -s              Don't draw branches to scale.