fix: use single object prop on

feat: provide hasMetaInfo export for other libraries to check if metaInfo has been defined

chore: deprecate _hasMetaInfo

src/browser.js

@@ -3,6 +3,7 @@ import createMixin from './shared/mixin'
 import setOptions from './shared/options'
 import { isUndefined } from './shared/typeof'
 import $meta from './client/$meta'
+export { hasMetaInfo } from './shared/hasMetaInfo'
 
 /**
  * Plugin install function.
@@ -13,7 +14,7 @@ function VueMeta(Vue, options = {}) {
 
   Vue.prototype.$meta = $meta(options)
 
-  Vue.mixin(createMixin(options))
+  Vue.mixin(createMixin(Vue, options))
 }
 
 VueMeta.version = version