merge liuqr's password strength and modified
merge liuqr's password strength and modified

XiaodunServerGroup/xiaodun-platform,XiaodunServerGroup/medicalmooc,XiaodunServerGroup/medicalmooc,liuqr/edx-xiaodun,XiaodunServerGroup/xiaodun-platform,hwjworld/xiaodun-platform,XiaodunServerGroup/xiaodun-platform,liuqr/edx-xiaodun,XiaodunServerGroup/xiaodun-platform,liuqr/edx-xiaodun,XiaodunServerGroup/xiaodun-platform,hwjworld/xiaodun-platform,hwjworld/xiaodun-platform,XiaodunServerGroup/medicalmooc,XiaodunServerGroup/medicalmooc,XiaodunServerGroup/xiaodun-platform,XiaodunServerGroup/medicalmooc,liuqr/edx-xiaodun,hwjworld/xiaodun-platform