Merge branch 'master' into 2.0-cn

* master:
  suggest () as replacement for () when used with parent and a direct child, fixes #455
  mention that handlebars syntax is intentionally limited, fixes #459
  improve JSX introduction, fixes #464

# Conflicts:
#	src/guide/render-function.md

Author: dingyiming

src/guide/comparison.md

@@ -294,7 +294,7 @@ That said, it would probably make a better comparison between Vue core and Ember
 
 - Vue provides unobtrusive reactivity on plain JavaScript objects and fully automatic computed properties. In Ember, you need to wrap everything in Ember Objects and manually declare dependencies for computed properties.
 
-- Vue's template syntax harnesses the full power of JavaScript expressions, while Handlebars' expression and helper syntax is quite limited in comparison.
+- Vue's template syntax harnesses the full power of JavaScript expressions, while Handlebars' expression and helper syntax is intentionally quite limited in comparison.
 
 - Performance-wise, Vue outperforms Ember by a fair margin, even after the latest Glimmer engine update in Ember 2.0. Vue automatically batches updates, while in Ember you need to manually manage run loops in performance-critical situations.
 

src/guide/migration.md

@@ -750,7 +750,9 @@ Vue.config.keyCodes.f1 = 112
 
 The problem is event flows that depend on a component's tree structure can be hard to reason about and very brittle when the tree becomes large. It simply doesn't scale well and we don't want to set you up for pain later. `$dispatch` and `$broadcast` also do not solve communication between sibling components.
 
-For the simplest possible upgrade from `$dispatch` and `$broadcast`, you can use a centralized event hub that allows components to communicate no matter where they are in the component tree. Because Vue instances implement an event emitter interface, you can actually use an empty Vue instance for this purpose.
+One of the most common uses for these methods is to communicate between a parent and its direct children. In these cases, you can actually [listen to an `$emit` from a child with `v-on`](http://vuejs.org/guide/components.html#Form-Input-Components-using-Custom-Events). This allows you to keep the convenience of events with added explicitness.
+
+However, when communicating between distant descendants/ancestors, `$emit` won't help you. Instead, the simplest possible upgrade would be to use a centralized event hub. This has the added benefit of allowing you to communicate between components no matter where they are in the component tree - even between siblings! Because Vue instances implement an event emitter interface, you can actually use an empty Vue instance for this purpose.
 
 For example, let's say we have a todo app structured like this:
 

src/guide/render-function.md

@@ -264,7 +264,22 @@ render: function (createElement) {
 
 ## JSX
 
-如果你写了很多 `render`  函数，可能会觉得痛苦，在多于 14 行代码的场景中还是模板简单、易读很多。
+如果你写了很多 `render`  函数，可能会觉得痛苦：
+
+``` js
+createElement(
+  'anchored-heading', {
+    props: {
+      level: 1
+    }
+  }, [
+    createElement('span', 'Hello'),
+    ' world!'
+  ]
+)
+```
+
+特别是模板如此简单的情况下：
 
 ``` html
 <anchored-heading :level="1">