code: function logout(callback) {
    // Reset the current session
    core.setSession({});
  
    core.events.emit('auth.logout');
    if (typeof callback === 'function') {
      callback(null);
    }
  }
docs: Resets the session, which is akin to logging out. This does not deactivate
  the access token given to your app, so you can continue to perform actions
  if your server stored the token.
  @method logout
  @param {Function} [callback]
  @example
  ```javascript
  Twitch.logout(function(error) {
  // the user is now logged out
  });
  ```