Fixed issue #771.Comment allow new line.

Raising Fresh PR on issue #771 as my previous branch got messed up while pushing from local.
I have tested all scenarios from my end. 
The comment div is taking care of next line.
In case of edit it accepts new line and on hitting enter it goes to next line. to post the changed comments user will follow same ctrl+enter.

I have already tried to do the same at line 400
(var ctrl_key = (e.keyCode === 10 || e.keyCode === 13 || e.keyCode === 115 || e.keyCode === 19);)
Here also will do the same thing as it really makes sense.