fix incorrect file status.
Update docs.
Update start-installation.md

update to 20140919 from English version
Update start-gii.md

update to 20140919 from English version
Update start-gii.md

update to 20140919 from English version
Merge pull request #24 from funson86/patch-1

Update start-installation.md
[SK] Updated locale strings
Merge pull request #25 from funson86/patch-2

OK，那我merge先，不过我已经把图片放进来了，这个库本来也不是给人看的，应该看官方库，那边的才会更准确一些。
yii2-chinesization/yii2的不需要放图片，地址也最好别放绝对路径，因为文档后期是通过官方开发的apidoc软件渲染，而不是通过GitHub观看的。
Merge pull request #5196 from lubosdz/master

[skip ci] [SK] Updated locale strings
Merge pull request #5197 from yii2-chinesization/master

[ci skip] more on update old docs
Alert::Widget improvements

- Now handle ActiveModel->getErrors() (multidimensional arrays)
- Add alias Alert:add() to Yii::$app->session->setFlash()