Bunch of changes in fast-dev-mode
Bunch of changes in fast-dev-mode

* Currency has now iso as the primary key
* Language has now iso as the primary key
* Changes all relations that are using Language and Currency
* Menu and MenuNode have not DateTime elements
* Fixed some headers in php files that were wrong
* Added YAML parser method in abstract fixtures file in core
* Added YAML Symfony component dependency using previous new method
* Some changes to EntityTranslation. Now is not necessary to use manual Id's for new entities. Introduced as well fallback parameters and master locale
* Changed Category and Product Id Strategy to AUTO (rollback for previous change for last EntityTranslation version)
* Placed all container-related methods (find, save, getFactory, getRepository, getObjectManager...) to a Trait placed in CoreBundle
* Updated WebTestCase and AbstractFixture with this trait. Changed all Fixtures for using these new methods
* Updated all Fixtures for using specific ObjectManager. Never using standard $manager variable.

elcodi/PluginBundle