code: public final SimpleDistanceConstraint invert() {
  		SimpleDistanceConstraint newConstraint = new SimpleDistanceConstraint();
  		newConstraint.setMinimum(-this.getMaximum());
  		newConstraint.setMaximum(-this.getMinimum());
  		newConstraint.setFrom(this.getTo());
  		newConstraint.setTo(this.getFrom());
  		return newConstraint;
  	}
docs: Inverts the <em>from</em> and <em>to</em> reference of this constraints and updates
  the {@link #minimum} and {@link #maximum} bounds accordingly.
  @return an inverted copy of this constraint.