Autenthicated endpoint on BitMex

[ottuzzi]

Hi there, I would like to get streaming data about private orders: I see on Bitmex websocket documentation we can get it but only with authentication[1].
Actually I tried without authentication but I got:

  2018-07-16T14:56:44,492Z ERROR i.b.x.bitmex.BitmexStreamingService - Error with message: User requested an account-locked subscription but no authorization was provided.

Can anybody help me?
Once working I would contribute back :)

[1]https://www.bitmex.com/app/wsAPI#Authentication

[jkolobok]

Fixed here #185 but @dozd haven't been merging PR for quite a while

[badgerwithagun]

Also #244