Houston, we have wp-cli. And a bunch of other stuff.

* Add PHP and WP modules. The latter is depedent on refactoring a class to install wp-cli from Git https://github.com/rmccue/puppet-wp/pull/1
* webserver.pp now adds PHP and a few related extensions
* default-projects.pp gives us our first default project: wp-cli

Essentially, run `vagrant destroy; vagrant up;` and now wp-cli is at your fingertips.