Add websocket support

[stanhebben]

Glad to have encountered this little gem.

However, I needed websockets, and this tool doesn't support them.

So I added it.

[icflorescu]

Thanks a lot, @stanhebben! I haven't been using IIS (or iisexpress-proxy) for a long time and - although lots of people complained about the lack of support for WebSockets, no one else would come up with a PR so far.

Merged and published on npm registry as v1.4.0. There's also a note in the README mentioning you; if you have anything to add (such as a brief description of a usage scenario), please feel free to add it and I'll republish it.

Thanks again, and - btw - would you be interested in becoming a co-maintainer for this repo?

[stanhebben]

I'll think about it. I will be working with IIS Express for the foreseeable future and there will be uses for the proxy from time to time. However, my schedule is very busy, so I don't know if I'll be able to spend any additional time and mental resources to engage into testing and fixing the issues that come up.

However, for the time being, if there's bugs or issues I'm encountering I will be glad to provide respective PRs for them.

[icflorescu]

It's open-source, free and non-profit, so it comes with no obligations :-). About time & mental resources to spend - this is definitely not lodash or react; it has less than 350 stars here and barely over 650 downloads per month on npm, so there's not much activity around it. Just the occasional PR once every six months or so - 4 including yours since 2015. So it's not about time or resources (I'm in the same situation as you - don't have a lot to spare), it's just that on the long term it would be safer for the repo to have more than just one collaborator, and I'd be happier to share the access with somebody that uses the project (or has used it at some point), that's all. And by coming up with the PR above you already did more than what 99% of the users do :-)

Thanks again and let me know if I can add you as a collaborator.