[WIP] Tutorial Updates for 1.2

Updates and improvements for 1.2.

Note there is a problem in that the RoutingAutoBundle intializes before the initializer that we create in the last chapter, causing it to fail.

We need to add support for initializer priority: https://github.com/doctrine/DoctrinePHPCRBundle/pull/173
Again I seem to forget to extend NodeInterface each time I do this tutorial, so hopefully this makes it clearer.