I found there is no RankSelection in default ECJ, so I would like to share
one I used with my work. Most part of my implementation is the based on the
BestSelection by Sean Luke, except the fitness is replaced by the rank of
individuals. Parameter rank.n may be used to limite the range of selection
as used in BestSelection, and "pick-worst" may also be used to reverse the
*Be sure to change the package path to fit your environment before using it.