Add onhover_info to settings.

settings_template.toml

@@ -25,6 +25,8 @@ images = ["", ""]
 # Names of table columns with features to plot
 plot_vars = ["",""]
 group_by = ""
+# Columns with values to show when hovering cursor over a data point
+onhover_info = ["", "", ""]
 # Details for high-throughput experiments
 # Note that plate_size must be a number not a column name.
 hcs = { plate_size = 0, plates = "", wells = "", fields = "", treatments = "" }