Tree Shaking support - Release : v3.0.0(Not backward compatible)

v3.0.0 ::

1. Refactoring of complete package to make this package - Tree shakable Fix:60.

2. Change in usage:

   • ES6 Module usage

     // Latest version - v3.0.0
     import { Country, State, City }  from 'country-state-city';

   • AMD Module usage

     // Latest version - v3.0.0
     let Country = require('country-state-city').Country;
     let State = require('country-state-city').State;
     
     console.log(Country.getAllCountries())
     console.log(State.getAllStates())