adding Kazakh and correcting some locales

- adding Kazakh (kk / kaz)
- removing one-letter codes as they are not standard (in favor of their existing two letter codes)
- correcting locales for Sami, Farsi, Greek according to iso639-2

see http://cakephp.lighthouseapp.com/projects/42648/tickets/3613-internalization-description-for-kazakh