完善评论功能，允许同时回复多人

Change-Id: I039fc18973495d09dc06da0705276924084ef97f
Merge branch 'master' of https://github.com/Hahn-/GdutExchange.git

Conflicts:
	Public/js/detail/detail.js

Change-Id: I16f3c9f76b3165ac08800766f1f8a7efaec327a5