Gets the forestplot legend grobs
prFpGetLegendGrobs(legend, txt_gp, title)
Legend corresponding to the number of bars
Set the fonts etc for all text elements. See fpTxtGp
for details
The title of the plot if any
list
A "Legend" class that derives from a
list with all the different legends. The list also contains
attributes such as height, width, max_height,
max_width, line_height_and_spacing. The title of the
legend is saved inside attr("title")