increased minimal version of node from 0.4.0 to 0.12.0

because can't run tests on lesser version anyway

Author: unclechu

package.json

@@ -38,7 +38,7 @@
   ],
   "main": "lib/deep-extend.js",
   "engines": {
-    "node": ">=0.4.0",
+    "node": ">=0.12.0",
     "iojs": ">=1.0.0"
   },
   "scripts": {