Rephrase info about there being no controllers. (vuejs#555)

Some users is too impersonal and it's safe to say many people who read the guide are not yet users.

Author: Francisc

src/guide/instance.md

@@ -94,7 +94,7 @@ var vm = new Vue({
 // -> "a is: 1"
 ```
 
-There are also other hooks which will be called at different stages of the instance's lifecycle, for example `mounted`, `updated`, and `destroyed`. All lifecycle hooks are called with their `this` context pointing to the Vue instance invoking it. Some users may have been wondering where the concept of "controllers" lives in the Vue world and the answer is: there are no controllers. Your custom logic for a component would be split among these lifecycle hooks.
+There are also other hooks which will be called at different stages of the instance's lifecycle, for example `mounted`, `updated`, and `destroyed`. All lifecycle hooks are called with their `this` context pointing to the Vue instance invoking it. You may have been wondering where the concept of "controllers" lives in the Vue world and the answer is: there are no controllers. Your custom logic for a component would be split among these lifecycle hooks.
 
 ## Lifecycle Diagram