注释掉部分页面结构，调整部分业务代码
增加了标识题目为中间题的字段和逻辑
实现视频中间试题的逻辑
处理中间题的业务逻辑
Merge pull request #1 from styling/master

Merge pull request #1 from WRLin/master
Merge pull request #2 from WRLin/master

add readme