add minified build

Author: yyx990803

package.json

@@ -16,11 +16,12 @@
     "hammerjs": "^2.0.6"
   },
   "devDependencies": {
+    "uglify-js": "^2.6.2",
     "vue": "^1.0.16",
     "webpack": "^1.12.12"
   },
   "scripts": {
-    "build": "webpack example/example.js example/example.build.js",
+    "build": "webpack example/example.js example/example.build.js && uglifyjs vue-touch.js -c -m > vue-touch.min.js",
     "dev": "webpack --watch example/example.js example/example.build.js"
   }
 }