Upgrade to babel 6 + attempt to fix issues with node <= 0.12.x

Author: Andrew Levine

package.json

@@ -48,22 +48,26 @@
   },
   "devDependencies": {
     "ava": "^0.15.2",
-    "babel": "^5.8.38",
+    "babel-core": "^6.10.4",
+    "babel-preset-es2015": "^6.9.0",
+    "babel-register": "^6.9.0",
     "xo": "^0.16.0"
   },
   "ava": {
     "require": [
-      "babel/register"
+      "babel-register"
     ]
   },
   "babel": {
     "only": [
       "lib/**",
       "cli.js",
       "cli-utils.js",
-      "test/_helpers.js"
+      "test/_helpers.js",
+      "node_modules/jscodeshift/**"
     ],
-    "sourceMaps": "inline"
+    "sourceMaps": "inline",
+    "presets": ["es2015"]
   },
   "xo": {
     "esnext": true,