Update cocos2d 

キーボードの修正入ってるはずだけどかかれてないな．

https://github.com/cocos2d/cocos2d-html5/blob/Cocos2d-html5-v3.0-rc0/CHANGELOG.txt
```
Cocos2d-html5-v3.0 RC0 @ July.3, 2014

* Added Facebook SDK plugin into Pluginx extension.
* Refactoration of gui system `ccui` for better performance, usage and maintainbility.
* Added `bake` function to `cc.Layer` to support layer baking.
* Added object pool extension: `cc.pool`.
* Added new easing functions: bezier action, quadratic actions, quartic actions, quintic actions, circle actions, cubic actions.
* Made `cc.loader` continue the counter process even if a resource failed to be loaded.
* Supported multiple property objects in `cc.Class.extend` function.
* Refactored `ccui.Widget`'s `getLeftInParent`, `getBottomInParent`, `getRightInParent`, `getTopInParent` to `getLeftBoundary`, `getBottomBoundary`, `getRightBoundary`, `getTopBoundary`.
* Refactored `cc.FadeIn.create(duration, toOpacity)` to `cc.FadeIn.create(duration)`.
* Refactroed all string access functions in `ccui` extension to `setString` and `getString`.
* Added `getContentSize` and `setContentSize` in `ccui` extension.
* Changed the default alpha value of `cc.Color` from `undefined` to 255.
* Made `cc.log` support formatted string.

* Bugs fix:
    1. Fix bugs on creating sequence objcet or spawn object using new method.
    2. Fix a bug that `ccui.LoadingBar`'s `setPercent` function will crash when its texture is in a plist file and scale9Enabled is true.
    3. Fixed a bug of `cc.audioEngine` that it crashs when audio isn't correctly loaded and its duration is infinity.
    4. Correction of the calculation of `cc.visibleRect`.
    5. Fix `cc.Skin`'s bounding box calculation for canvas rendering.
    6. Fix an issue that `cc.TextureCache` doesn't handle loaded texture in some case.
    7. Fix an issue that texture rect could be zero sized in `initWithFile` function of `cc.Sprite`.
    8. Fix a bug on inverted ClippingNode with DrawNode as stencil in Canvas render mode.
    9. Fix a bug that `cc.SpriteFrame` didn't support initialization with texture name parameter.
    10. Fix a bug on `ccs.ArmatureAnimation`'s loop parameter.
    11. Fix a bug that `cc.JumpTo`'s `_delta` position calculation is incorrect.
    12. Fix a bug of `cc._audioLoader` that it doesn't work when it failed to load an audio file.
```