Create a better looking comments

[yammesicka]

• Create a slidedown, accordion-like comments section instead the current ugly popover.
• Drop Bootstrap's popover.
• Drop jQuery.

[ron-huberfeld]

Hi @yammesicka, please assign to me

[ron-huberfeld]

@yammesicka, I'm going to follow this article. Any objections?

[yammesicka]

@ron-huberfeld That's look great!

Be sure to keep it simple, though: we currently don't need hierarchies of comments, mentions, votes or any other mechanism which is not just multiple comments per line.
If I had to implement this, I would probably look at existing comments mechanism on code-review systems and try to do something similar :)

[yammesicka]

WIP, see #366