BindAddress option

[grifball]

I'm sorry if this option already exists and I just didn't notice it.
I'm using karma on a private project on a server with port 9876 open.
Rather than going through and closing that port in the firewall, it's easier just to bind to 127.0.0.1 instead of 0.0.0.0.
So I added support into karma for that, it's a simple change, I included a diff of the files.
I'm using karma version 1.3.0
diff new old.txt

Let me know what you guys think of having this option.

[maksimr]

@grifball Karma don't have this option now
We had a pull request(PR) about it with long discussion.
It will be nice if you look at this PR and reanimate it

Thanks!

relates #1593

[grifball]

I looked at #1311 and #1214 and they both seem fine to solve this issue, so I added them in and fixed the unit tests so that the dummy web server accepts the correct arguments. I'll make a PR.