Bumped version into v3.0.0

* Refactor the build flow and project structure
* Rewrote tests with jest
* Fixed the issue of not updating when receive new props (#8)
* Updated example

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-twzipcode",
-  "version": "2.0.2",
+  "version": "3.0.0",
   "description": "Rewrite jQuery-TWzipcode in React.js.",
   "main": "dist/main.js",
   "homepage": "https://github.com/patw0929/react-twzipcode",