Added getOrder for btc-markets exchange

[upsatish]

Fixes #935

[askmike]

Hey @anotherkabab,

Some context: Since 0.5 the trader was updated and it now requires two changes:

• the getOrder method - it should return a specific object specified here: https://gekko.wizb.it/docs/extending/add_an_exchange.html#getOrder
• the cancelOrder method now takes a callback.

I've failed to do this for all exchanges, so some (including btc-markets) are now outdated. We would need to fix both issues above before we can add it back!

[upsatish]

Hi @askmike thank you for the review. I'll do those changes as you suggested.

Is there any way to test this apart from running the trader live?

[askmike]

I haven't found any, since it's all about dealing with real response data from the exchange. Some exchanges provide a sandbox API, if btc-markets does this that would be an option.

[askmike]

Closing this for inactivity.

[upsatish]

Sorry, wasn't able to complete this.