public ParetoFront<T> merge(final ParetoFront<? extends T> elements) {
		addAll(elements);
		return this;
	}
Add the all {@code elements} to {@code this} pareto-set.

@implNote
Merging two pareto fronts has a time complexity of
{@code O(elements.size()*this.size())}.

@param elements the elements to add
@return {@code this} pareto-set
@throws NullPointerException if the given parameter is {@code null}
jenetics.ext/src/main/java/io/jenetics/ext/moea/ParetoFront.java