Usdm support

[siegfried]

This PR is related to #22

[siegfried]

I'm a little hesitant to modify the current code base even through a few of them are reusable. I presume to reuse them some renaming and updates might be necessary, so I think adding some tests at first might be a good idea, in order to not break current behavior. This is a WIP PR, so please feel free to leave any comment. @daroczig

[siegfried]

These functions are using deprecated V1 API. Is there a plan to remove them in favor of V3?

• binance_ticker_all_prices()
• binance_ticker_all_books()
• binance_ticker_24hr()

Also these functions which are fundamental should be migrated easily:

• binance_ping()
• binance_time()
• binance_klines()
• binance_ticks()
• binance_trades()
• binance_depth()
• binance_exchange_info()

@daroczig

[siegfried]

Or shall we version the functions according to the API?

[siegfried]

On a second thoughts we might have to skip the tests requiring authentication until it is possible to have a shared credential for testing. Even though the timestamp can be input as an argument. different credentials would produce different signatures.

[siegfried]

If you feel I'm heading to the right direction, you can merge this PR. I'll add the missing feature one by one. @daroczig

[siegfried]

May I use packages from tidyverse in this package?

[siegfried]

Now LIMIT orders and MARKET orders work on USDM.