Revert "Bump babel deps and re-enable transform-react-constant-elements" (facebook#1575)

Author: gaearon

Diff for: package.json

@@ -24,7 +24,7 @@
   },
   "dependencies": {
     "autoprefixer": "6.7.2",
-    "babel-core": "6.23.1",
+    "babel-core": "6.22.1",
     "babel-eslint": "7.1.1",
     "babel-jest": "18.0.0",
     "babel-loader": "6.2.10",