Fix bug with Field Type Guessing in forms. Proxy moved to doctrine/commo...

Fix for field type guesser in forms.

Pls remember to update dependencies - symfony-cmf/symfony-cmf:
$ composer depends doctrine/phpcr-bundle
sonata-project/doctrine-phpcr-admin-bundle requires doctrine/phpcr-bundle (1.0.*)
symfony-cmf/block-bundle requires doctrine/phpcr-bundle (1.0.*)
symfony-cmf/content-bundle requires doctrine/phpcr-bundle (1.0.*)
symfony-cmf/core-bundle requires (dev) doctrine/phpcr-bundle (1.0.*)
symfony-cmf/menu-bundle requires doctrine/phpcr-bundle (1.0.*)
symfony-cmf/routing-bundle requires (dev) doctrine/phpcr-bundle (1.0.*)
symfony-cmf/simple-cms-bundle requires doctrine/phpcr-bundle (1.0.*)
symfony-cmf/symfony-cmf requires doctrine/phpcr-bundle (1.0.0-alpha4)
symfony-cmf/tree-browser-bundle requires (dev) doctrine/phpcr-bundle (1.0.*)