update module/post.php as a prototype

still fail to load post tile and id, I think it has sth. with the
database.
update SQL.php

POST最后一个函数稍微改动了一下便于调试,有一个成员函数调用忘记加this,我改过来了.
Update post.php

能读取信息,但是输出还是有些问题
anyway
Merge branch 'master' of https://github.com/NJUOPEN/Portal-BBS