Provides useful Iterator decorators

• FilterIterator: Little bit better than CallbackFilterIterator: allow to map any Traversable
• MapIterator: Maps keys/values before yielding for any Traversable object

# Install Composer
curl -sS https://getcomposer.org/installer | php

# Add Guzzle as a dependency
php composer.phar require wlfrm/iterator:~1.0

After installing, you need to require Composer's autoloader:

require 'vendor/autoload.php';