Updates and fixes

Included commits from [PR#3](https://github.com/yevgenko/cookbook-magento/pull/3)

* Installs current version of community
* Fix for nginx_site due to change [here](https://github.com/opscode-cookbooks/nginx/blob/master/definitions/nginx_site.rb#L22)
* Bumped php-fpm cookbook version to match new method for setting up pools
* Updated Vagrant file to use newer version of centos and use ominbus to install newer version of chef