Move example to dev-example folder

Remove watcher from FormWizard component to avoid double beforeChange trigger
Code cleanup

dev-example/main.js

@@ -0,0 +1,15 @@
+// The Vue build version to load with the `import` command
+// (runtime-only or standalone) has been set in webpack.base.conf with an alias.
+import Vue from 'vue'
+import App from './App.vue'
+import FormWizard from '../src/index'
+Vue.use(FormWizard)
+
+Vue.config.productionTip = false
+
+/* eslint-disable no-new */
+new Vue({
+  el: '#app',
+  template: '<App/>',
+  components: {App}
+})