result from elo_steepness_from_matrix,
elo_steepness_from_sequence or
davids_steepness
adjust
numeric, parameter for smoothing posterior of individual scores
color
logical, default is TRUE where individuals get color-
coded. If FALSE: a gray scale is used. It is also possible
to hand over a vector with colors, which then must be correspond
in length to the number of individuals.
width_fac
numeric, relative width of posterior distributions. This is
actually affects the 'height' but since the posteriors are rotated it
visually represents width.
axis_extend
numeric, an extension factor to extend the horizontal
axis to leave space for the posteriors. When set to 0 the axis stops
at n (the number of individuals, which represents the
lowest rank).