feat: use named exports to export helper functions

src/browser.js

@@ -9,7 +9,7 @@ export { hasMetaInfo } from './shared/hasMetaInfo'
  * Plugin install function.
  * @param {Function} Vue - the Vue constructor.
  */
-function VueMeta(Vue, options = {}) {
+function install(Vue, options = {}) {
   options = setOptions(options)
 
   Vue.prototype.$meta = $meta(options)
@@ -17,12 +17,13 @@ function VueMeta(Vue, options = {}) {
   Vue.mixin(createMixin(Vue, options))
 }
 
-VueMeta.version = version
-
 // automatic install
 if (!isUndefined(window) && !isUndefined(window.Vue)) {
   /* istanbul ignore next */
-  Vue.use(VueMeta)
+  install(window.Vue)
 }
 
-export default VueMeta
+export {
+  version,
+  install
+}