Merge branch 'develop' into suzhi
调整一下首页UI
CoreData中target和file的引用关联设为no action，按create time排序
Merge branch 'suzhi' into develop
AppStore milestone 1
Merge branch 'develop' into wk_bugs
添加了改变数据库文件功能

添加了改变数据库文件功能，并且在程序重新进入前台的时候不能不可修改账号。