Add deploy command

Feature which provides integration with [Composer Command Integrator](https://github.com/magento-hackathon/composer-command-integrator). 

This allows deploying Magento Core packages using the following:

    ./vendor/bin/composerCommandIntegrator.php magento-core-deploy

this mostly copy + paste from the default Magento Module deploy command.

I added this so I didn't need to run `composer update` every time I want to deploy as Composer is pretty slow sometimes.