[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
````

lets move this command into OptionalCommands and do this check in the bundle class: https://github.com/doctrine/DoctrinePHPCRBundle/blob/master/DoctrinePHPCRBundle.php#L61