intervals: The interval(s) to be plotted. Two column matrix.
estimates: Estimates for each of the intervals (optional).
y_scale: How tall the interval plots are to be drawn
interval_value_labels: Logical value specifying whether interval value labels are to be added.
estimate_value_labels: Logical value specifying whether estimate value labels are to be added.
interval_labels_offset: Amount to offset interval labels by from the centre of the end of the interval's plot. c(x1, x2, y1, y2).
estimate_labels_offset: Amount to offset estimate labels by. c(x, y). Normally want the estimate to be x-located at its value, but may want a y-offset to move it above or below the plot shape that represents the interval.
plot_estimate_marks: Whether to plot marks at the x location of the estimates.
estimate_mark_points: y positions of the ends of the estimate marks as a numeric vector of length 4. Values are, in order: start (relative to centre), end (relative to box top), start (relative to centre), end (relative to box bottom).