Cryptofeed

* Feature: add Bithumb exchange - l2 book and trades
* Bugfix: Fix inverted Poloniex symbols
* Feature: simplify and cleanup parts of Poloniex
* Feature: add `symbols` class method to all exchanges to get list of supported trading pairs
* Feature: Clean up internal class attributes in Feed class
* Feature: Add graceful stop and shutdown methods for Feeds
* Feature: Add ledger endpoint to Kraken Rest module, add ability to optionally filter by symbol, or all symbols, for historical trades
* Docs: Update documentation regarding adding a new exchange to cryptofeed
* Bugfix: Reset delay after connection is successful
* Feature: yapic.json parses strings to datetimes automatically, no longer need to rely on Pandas for datetime parsing
* Bugfix: 491 - dictionary resized during iteration in ByBit
* Bugfix: 494 - added status argument to liquidations callback
* Bugfix: 399 - book delta issue with Kucoin and Gateio
* Feature: Binance Delivery candle support
* Feature: Binance US candle support
* Feature: Kraken Candle support
* Update: Remove deprecated channel mapping from Kraken, use channel name from message instead
* Bugfix: change Kraken Futures to use the standard symbol to be consistent with the rest of the library
* Update: use Kucoin v3 endpoint for orderbook snapshot (v2 deprecated).
* Update: Poloniex ticker message format update

* Bugfix: Fix Binance subscriptions when subscribing to more than one candle
* Feature: Remove support for Influx versions prior to 2.0
* Feature: Add stop method to HTTP Backends to gracefully drain queue and write pending data on shutdown
* Feature: Revamp InfluxDB code. Drop support for storing floating point as str, store book data as json blob
* Bugfix: Remove unused get_instrument calls in Deribit and Kraken Futures
* Feature: Revamp symbol generation and exchange info for Deribit and Kraken Futures
* Bugfix: Fix issue using AsyncFile callback to store raw data
* Testing: Add exchange tests for Deribit and Binance
* Bugfix: Fix symbol issue in Bitmex when initializing the orderbook
* Bugfix: Fix various issues with FTX, OKCOIN/OKX and Huobi symbol generation
* Testing: Overhaul exchange tests, all exchanges are now tested with real data. Fixed various bugs as a result of this testing. Revamped AsyncFileCallback.
Added new tool to generate test data for testing.
* Bugfix: Improve connection cleanup in AsyncConnection object
* Feature: Add support for user defined exception handling in FeedHandler
* Bugfix: Fix redis backends that can't handle None
* Bugfix: Connection exceptions being ignored in Feedhandler
* Bugfix: Binance address generation correction
* Bugfix: OKX symbol generation incorrect + validate symbols used for channels that dont support all types
* Breaking Change: Large rewrite of Feedhandler, Connection, and Feed. Many timeout related options moved from feedhandler to Feed. Symbol specific code
moved to exchange class. Rewrite of raw data collection.
* Feature: Candle support for Huobi
* Feature: Allow user to specify Postgres port in Postgres backends
* Bugfix: Report base volume, not quote volume in Huobi candles
* Feature: Support for the KuCoin exchange

* Update to use alpha release of aioredis 2.0. Allows building of wheels again

* Bugfix: Add manifest file for source dist

* Bugfix: Init uvloop earlier so backends that use loop will not fail
* Docs: Remove FAQ, added performance doc section
* Bugfix: 404 - Use AsyncConnection object for Binance OI
* Feature: Rework how raw data is stored (when enabled). REST data can now be captured
* Feature: New feedhandler method, `add_feed_running` allows user to add feed to running instance of a feedhandler
* Feature: create_db defaults to False on InfluxDB backends
* Feature: Normalize Bitmex Symbols
* Update: Remove extraneous methods in feed objects used to query symbol information
* Feature: Use realtime ticker for Binance
* Bugfix: Bitmex symbols not being normalized correctly
* Bugfix: Fix GCP PubSub backend
* Bugfix: Fix historical data REST api for Bitmex
* Feature: Use separate tasks (fed by async queue) for backend writing. Redis now uses this method
* Bugfix: Allow user specified max depths on Kraken
* Feature: Add backend queue support to ZMQ backend
* Feature: Add backend queue support to Socket backends
* Feature: Add VictoriaMetrics support via backend
* Feature: Add backend queue support to influx and elastic
* Feature: Candle support
* Bugfix: Ignore untradeable symbols in Binance symbol generation
* Feature: Add backend support for queues in Postgres. Rework postgres backend and supply example SQL file to create tables for demo
* Bugfix: Fix ByBit symbol generation
* Feature: Authenticated channel support for OKX/OKCOIN
* Update: Poloniex changed signaure of ticker data
* Feature: Candles for Binance Futures
* Feature: Premium Index Candle support for Binance Futures
* Feature: Update Gateio to use new v4 websocket api. Adds support for candles
* Bugfix: Fix open interest on OKEx
* Bugfix: OKEx was duplicating subscriptions
* Breaking Change: Core callbacks (trade, candle, books, ticker, open interest, funding, liquidations, index) now use custom objects

* Feature: Use UVLoop if installed (not available on windows)
* Bugfix: Allow exchanges to customize their retry delays on error
* Feature: New demo code showing user loop management
* Feature: Handle more signals for graceful shutdown
* Bugfix: BinanceFutures message format change
* Feature: Missing sequence number on Coinbase will not reset all data streams, just the affected pair
* Feature: Use timestamp from exchange for L2 book data from Coinbase
* Bugfix: Blockchain exchange had incorrect timestamps, and incorrect log lines
* Bugfix: Wrong datatype in BackendFuturesIndexCallback
* Bugfix: Fix bad postgres callback for open_interest and futures_index
* Feature: Signal handler installation now optional, can be done separately. This will allow the feedhandler to be run from child threads/loops
* Bugfix: Fix binance delivery book ticker (message format change)
* Breaking change: Feed object `config` renamed `subscription`
* Feature: Configuration passed from feedhandler to exchanges
* Breaking change: Most use of `pair` and `pairs` changed to `symbol` and `symbols` to be more consistent with actual usage. pairs.py renamed to symbols.py
* Feature: Allow configuring the API KEY ID from Config or from environment variable
* Bugfix: Collisions in normalized CoinGecko symbols (this adds about 700 new symbols)
* Feature: Add candles function to coinbase
* Feature: Explain when Cryptofeed crashes during pairs retrieval
* Bugfix: BINANCE_DELIVERY Ticker use msg_type='bookTicker' as for the other BINANCE markets
* Feature: Support Bitmex authentication using personal API key and secret
* Feature: Print the origin of the configuration (filename, dict) for better developer experience
* Bugfix: Add guard against non-supported asyncio add_signal_handler() on windows platforms
* Feature: Simplify source code by standardization iterations over channels and symbols
* Bugfix: Remove remaining character "*" in book_test.py
* Bugfix: Fix return type of the function book_flatten()
* Feature: Shutdown multiple backends asynchronously, and close the event loop properly
* Bugfix: Repair the Bitfinex FUNDING
* Feature: Speedup the handling of Bitfinex messages by reducing intermediate mappings
* Feature: Support OKEx options
* Bugfix: Cancel the pending tasks to gracefully/properly close the ASyncIO loop
* Feature: Support for authenticated websocket data channels