add event dispatcher for v3
Merge pull request #264 from u0u0/master

add event dispatcher for v3
add memory management for v3.0
Merge branch 'master' of https://github.com/chukong/cocos-docs
Merge pull request #265 from u0u0/master

add memory management for v3.0
Update zh.md

1. Fix some minor spelling error.
2. Play the background music endlessly. This is the normal game logic.
Update zh.md

Fix some format error.
Merge pull request #267 from sunkehappy/patch-2

Update zh.md
Merge pull request #266 from sunkehappy/patch-1

Update zh.md
Merge pull request #5 from chukong/master

merge the official update