New comment UI is difficult to use when replying

I find it hard to reply to a comment in JIRA now because the add comment box is at the top of the screen, while the comments (including the most recent one I want to reply to) are at the bottom.

Two requests for further UI work in 4.2:

• put the comment box back where it was - at the bottom of the screen, rather than the top
• put an 'Add Comment' button at the bottom of the comments (as requested in JRA-11682).

This follows a pretty standard usability guideline: put controls near the content they act upon. Reply and add comment links should be somewhere near the comments, not up in a toolbar that has a bunch of unrelated functionality.