Have test jshintrc extend project's global one

.jshintrc

@@ -17,5 +17,8 @@
   "esnext": true,
   "eqnull": true,
   "browser": true,
-  "worker": true
+  "worker": true,
+  "globals": {
+    "JSON": false
+  }
 }

package.json

@@ -13,7 +13,7 @@
   "devDependencies": {
     "bower": "1.3.8",
     "chai": "1.10.0",
-    "jshint": "2.5.2",
+    "jshint": "2.8.0",
     "mocha-phantomjs": "3.5.2",
     "mocha": "2.1.0",
     "phantomjs": "1.9.19"

test/.jshintrc

 {
-  "curly": true,
-  "eqeqeq": true,
-  "immed": true,
-  "indent": 2,
-  "latedef": true,
-  "newcap": true,
-  "noarg": true,
-  "quotmark": true,
-  "undef": true,
-  "unused": true,
-  "trailing": true,
-  "asi": true,
-  "boss": true,
-  "esnext": true,
+  "extends": "../.jshintrc",
+  "es3": false,
+  "strict": false,
   "sub": true,
-  "eqnull": true,
-  "browser": true,
-  "worker": true,
   "globals": {
     "fetch": false,
     "Headers": false,