Fix PSR4 in composer.json, add dump()

Author: nicolas-grekas

composer.json

@@ -4,11 +4,15 @@
     "type": "project",
     "description": "Symfony Demo Application",
     "autoload": {
-        "psr-4": { "": "src/" },
+        "psr-4": {
+            "AppBundle\\": "src/AppBundle/",
+            "CodeExplorerBundle\\": "src/CodeExplorerBundle/"
+        },
         "classmap": [ "app/AppKernel.php", "app/AppCache.php" ]
     },
     "autoload-dev": {
-        "psr-4": { "Tests\\": "tests/" }
+        "psr-4": { "Tests\\": "tests/" },
+        "files": [ "vendor/symfony/symfony/src/Symfony/Component/VarDumper/Resources/functions/dump.php" ]
     },
     "require": {
         "php"                                  : ">=5.5.9",