Fix npm warnings about package.json

Author: mislav

package.json

@@ -1,15 +1,11 @@
 {
   "name": "jquery-pjax",
+  "description": "jQuery plugin for ajax + pushState navigation",
   "version": "2.0.0",
   "main": "jquery.pjax.js",
   "repository": "defunkt/jquery-pjax",
-  "licenses": [
-    {
-      "type": "MIT",
-      "url": "https://github.com/defunkt/jquery-pjax/blob/master/LICENSE"
-    }
-  ],
-  "files" : [
+  "license": "MIT",
+  "files": [
     "LICENSE",
     "jquery.pjax.js"
   ],