feat(core): export Vue and config in wx

Author: allen-zh

packages/mars-core/src/wx/index.js

@@ -5,4 +5,6 @@
 
 export {default as createApp} from './createApp';
 export {default as createPage} from './createPage';
-export {default as createComponent, vueCompCreator} from './createComponent';
+export {default as createComponent, vueCompCreator} from './createComponent';
+export {default as Vue} from '../base/vue/index';
+export {default as config} from '../config';