Days5: Selection Sort

I read and copy and paste from below about Selection Sort:

http://lecture.ecc.u-tokyo.ac.jp/~cichiji/cp-05/cp-05-06-3.html

This is my implementation.

https://gist.github.com/1430305/3f3883b6c2aecd7bd5b5e4adac06ae3fddff61a6