Implement websockets

[lookfirst]

This will probably help: n0mad01/node.bittrex.api#67

This code is a train wreck of complexity: https://github.com/codemanki/cloudscraper/

[harry-sm]

@lookfirst
I could help with this I did add it to my own lib.
I recently resorted to cloudscraper to address the 503 error.

[lookfirst]

@harry-sm Happy to get the PR's... to be honest, I've moved off bittrex and I'm using another exchange now. The feeling they gave me based on the quality of their API and attitude in their chat room made me not trust them as an exchange at all. It feels like they are one hack away from their wallet being emptied...

[lookfirst]

@harry-sm Your code looks pretty decent. A few style issues, but overall not bad. If you'd like to merge our two projects, I'm totally fine with that.

[harry-sm]

@lookfirst
Thanks. Merging is not a bad idea but not everyone want to use rxjs it's kinda a niche, but lets chat about it.