refactor[core]: use webpack-dev-server now (#355)

* bump deps: update vue-splitpane version

* refactor[chore]: use webpack-dev-serve build

* perf:settings

* doc: uodate readme

src/components/ImageCropper/index.vue

@@ -105,7 +105,7 @@
 <script>
     /* eslint-disable */
     import {effectRipple, data2blob} from './utils';
-    import request from 'utils/request';
+    import request from '@/utils/request';
     import langBag from './lang';
     const mimes = {
         'jpg': 'image/jpeg',