Fix reverse user link

Fixes #1605

Our user URLs are /user/{username}/ not /user/{id}/
Fix comment reply link cursor

Without an href, the link does not show a pointer cursor.
Focus comment reply box after clicking reply

Better UX than forcing to user to click inside the textarea after
clicking the "reply" link.
Show comment flagging link inline

The vertical bars implied that the date, reply link, and flag link
should all appear on the same line.
Merge pull request #1637 from jwalgran/topic/map-feature-comment-fixes

Map feature comment fixes