PHP Country State List: Get the list of countries and states of the world

This class can get the list of countries and states of the world.

It contains the names and codes of all countries of the world and the respective list of country states.

The class can return the list of all countries, all states, the states of a given country, get the country by ISO 2 or 3 letter code, find a state by name, and check if a given name is a valid country or state.