Upgrade babel-loader and drop testing for Node 4

Author: jakezatecky

.travis.yml

@@ -1,6 +1,5 @@
 language: node_js
 node_js:
-  - '4'
   - '6'
   - '7'
 before_script:

package.json

@@ -28,7 +28,7 @@
   "devDependencies": {
     "babel-core": "^6.13.2",
     "babel-eslint": "^7.0.0",
-    "babel-loader": "^6.2.4",
+    "babel-loader": "^7.0.0",
     "babel-preset-es2015": "^6.13.2",
     "babel-preset-react": "^6.11.1",
     "babel-preset-stage-2": "^6.5.0",