public ObservableList<TimeSection> getTimeSections() {
        if (null == timeSections) { timeSections = FXCollections.observableArrayList(); }
        return timeSections;
    }
Returns an observable list of TimeSection objects. The sections
will be used to colorize areas with a special meaning.
TimeSections in the Medusa library usually are less eye-catching than
Areas.
@return an observable list of TimeSection objects
src/main/java/eu/hansolo/tilesfx/Tile.java