Update install.php

修复数据库检查
Update config.php

修复某些情况下报的Warning错误
调整js载入顺序

bootstrap.js得在smoothscroll.js之前，否则后台会弹框报错。
Merge pull request #4 from wjfz/master

修复若干错误
增加站内信功能
Added preventing Cross site request forgery
Remove part of redundant code.
Remove the global calling nodes
Adjust the structure of sidebar
recoding the header and footer.
Add the Form Validation on user settings and fixed the error of changing password.
Recoding the upload class.
Recoding the avatar class