Composer: Exclude drivers from classmap

composer.json

@@ -17,6 +17,10 @@
         }
     ],
     "autoload": {
+        "exclude-from-classmap": [
+            "adminer/drivers/",
+            "plugins/drivers/"
+        ],
         "classmap": [
             "plugins/"
         ]
@@ -25,6 +29,9 @@
         "Apache-2.0",
         "GPL-2.0-only"
     ],
+    "require": {
+        "php": ">=5.3"
+    },
     "scripts": {
         "compile": "php compile.php"
     }