Updating Node version in Engines spec in package.json (#528)

* Updating Node version in package.json

Updated Node version from 0.12 to 1.4 in package.json engines

* Updated node version

Updated Node version from 0.12 to 4 in package.json Engines Spec

Fixes Issue #509

package.json

@@ -59,7 +59,7 @@
   },
   "engines": {
     "npm": ">=1.4.28",
-    "node": ">=0.12"
+    "node": ">=4"
   },
   "files": [
     "lib",