Merge pull request #3 from loosen/master

修复数据库连接状态判定条件错误,[修复]新增autoload核心组件配置，文件名和类名不一致时会加载错误
add switch constant
fix multi dabase bug
Merge pull request #4 from housetail/master

开关键设置为常量，修复MyDB的多库下sql相同时的bug
Merge pull request #2 from wxkingstar/master

合并主干