New Selection Models

```
Add a few extra selection models. The following might be a good place to look 
for some:

http://www.geatbx.com/docu/algindex-02.html#P244_16021
http://www.obitko.com/tutorials/genetic-algorithms/selection.php


```

Original issue reported on code.google.com by `luke.mcc...@gmail.com` on 8 Oct 2011 at 9:20
