Changes:

• Adding SpotAsyncClient and FuturesAsyncClient
• Renaming classes that were prefixed with "Kraken"
• Updated the documentation to concentrate on the request function, rather than individual methods.
• removed the spot websocket client v1 and orderbook client v1 (Resolve "Remove deprecated Spot websocket client (v1) and order book client (v1)" #236)
• remove the spot staking clients (Resolve "Remove deprecated Spot staking client" #237)
• Websocket clients do not start automatically anymore. They can now be started/stopped using start/stop-methods (Resolve "Websocket Logic Refactor - start/stop mechanism" #233)
• The base class of websocket clients is now derived from either SpotAsyncClient or FuturesAsyncClient, enabling the client to perform requests directly from the websocket client (PR: TBD))

Considerations:

#228 introduces the idea of async requests. It was decided to use aiohttp instead of other packages, like xhttp, since seems to provides a larger community and stable releases - in contrast to xhttp.

Notes/Todo's:

• add async Futures client (Add async REST API #228)
• add async Spot client (Add async REST API #228)
• do not prefix classes with "Kraken" (Get rid of the "Kraken"-prefix in class names #231)
• rename lots of clients (remove Kraken-prefix; remove V{1,2})
• drop spot websocket v1 client (Remove deprecated Spot websocket client (v1) and order book client (v1) #234)
• drop spot orderbook v1 client (Remove deprecated Spot websocket client (v1) and order book client (v1) #234)
• drop spot staking client (Remove deprecated Spot staking client #235)
• removed beta channel from Kraken Spot ws client (wasn't every working)
• check that exception_occur stuff in Spot and Futures websocket clients
• update Spot websocket tests regarding the new start/stop feature
• ... same for Futures
• let Spot orderbook client inherit from SpotWSClient (to leverage `.requests)
• update doc strings in Spot websocket client
• update doc strings in Futures websocket client
• update doc strings in Orderbook client
• fix the coverage metric which is broken since the CLI-feature
• let websocket clients base class be async (The base class for websocket clients should be capable to execute requests asynchronously #238)
• simplify adjust readme, shorten examples/
• simplify adjust documentation
• update doc string links to "new" Kraken API documentation (WON'T: old links still work; they may change the references again in the future, so lets wait a few months until they're finally happy with the docs)
• update the rebalance bot https://github.com/btschwertfeger/kraken-rebalance-bot (nothing to do, still works)