Added ThePrimeFactorsKata.

http://butunclebob.com/ArticleS.UncleBob.ThePrimeFactorsKata
Added argument validation.
Added TheBowlingGameKata.
Added the `review` directory to the list of ignored directories.
Added PHPUnit and Behat as project dependencies for development.
Added katas and differences to the original versions.
Added pre-initialization of rolls and improved constant access.
Renamed variable.
Added BDD feature context (for Behat) for TheBowlingGameKata.
Removed @since comment tag.