[WCM] Embedded PHPCR Shell

Replaces existing commands with embedded PHPCR Shell.

Depends on: https://github.com/phpcr/phpcr-shell/pull/40

For example

````
$ php app/console phpcr node:list / # commands with arguments can be entered without quotes
$ php app/console phpcr "ls -L2" # commands with options must be quoted
$ php app/console phpcr node-type:list
$ php app/console phpcr "SELECT * FROM [nt:unstructured]" # queries must be quoted
````

Changed to "If you want native access to the PHPCR-Shell to manager the PHPCR repository" - as you could "use" the PHPCR-Shell to manage the PHPCR repository without this dependency :)