DoctrineFixturesBundle installation

Conflicts:
	composer.json
Database: parameters.yml and create-empty-database.sql
Merge branch '2.2-Cheatsheet' into 2.2-Startup
Merge branch '2.2-DoctrineFixturesBundle' into 2.2-Startup
Merge branch '2.2-db' into 2.2-Startup
Merge branch '2.2-Gitignore' into 2.2-Startup