Added partial selection and Stooge sort, Floyd and Brent cycle detection, Pollard's Rho, Towers of Hanoi, Catalan numbers, Caesar and ROT13 ciphering algorithms

Hi all,

New algorithms in there!

* [Partial selection sort](http://en.wikipedia.org/wiki/Selection_algorithm#Partial_selection_sort)
* [Stooge sort](http://en.wikipedia.org/wiki/Stooge_sort)
* [Floyd cycle detection algorithm](http://en.wikipedia.org/wiki/Cycle_detection#Tortoise_and_hare)
* [Brent cycle detection algorithm](http://en.wikipedia.org/wiki/Cycle_detection#Brent.27s_algorithm)
* [Pollard's Rho algorithm](http://en.wikipedia.org/wiki/Pollard%27s_rho_algorithm)
* [Towers of Hanoï](http://en.wikipedia.org/wiki/Tower_of_Hanoi)
* [Catalan numbers](http://en.wikipedia.org/wiki/Catalan_number)
* [Caesar ciphering algorithm](http://en.wikipedia.org/wiki/Caesar_cipher)
* [ROT13 ciphering algorithm](http://en.wikipedia.org/wiki/ROT13)

Tests and comments have been included, as usual.

Regards,
Roland.