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.
Actually Now I got it why I was capturing the enterkey, the div was disappearing. This was fix towards the issues you had raised after I had raised the PR first time.

"Correction: if you edit a comment and then press enter without doing anything, editing finishes and the comment disappears."

I do the changes you had suggested.