Add reply number autofill when clicking on post number.

When user is in reply page, user can now click the post number in
front of each post to get the post anchor autofilled inside the
reply area.
Add inline reply when clicking on post number in listing page.

When user click on post number on listing page, a popover reply form
is displayed to allow user to perform a quick replying to a thread
without have to go to reply page directly.
Add explicit close button to popover form.
Merge branch 'feature/click-reply' into develop