Fixed class containment issue in "init.pp"

Because of [Class Containment](http://puppetlabs.com/blog/class-containment-puppet), the `require => Class['composer']` in `composer::project` didn't work (composer would try to run before being installed).
Containment implemented using [anchor pattern](http://projects.puppetlabs.com/projects/puppet/wiki/Anchor_Pattern), because already dependent on stdlib