Cryptofeed

* Bugfix: Enabling multiple symbols on Bitmex with deltas and max depth configured could cause crashes.
* Bugfix: Default open interest callback missing
* Change: Mongo backend stores book data in BSON
* Feature: Open Interest callbacks added to all backends
* Change: Instrument removed in favor of open interest
* Bugfix: Huobi feedhandlers not properly setting forced indicator for book updates, breaking deltas
* Bugfix: Some Kraken futures funding fields not always populated
* Feature: Open interest updates for Kraken futures
* Feature: Open interest updates for Deribit
* Bugfix: FTX ticker can have Nones for bid/ask
* Feature: InfluxDB 2.0 support
* Bugfix: Deribit funding only available on perpetuals
* Feature: Enable deltas (with out max depth) on exchanges that do not support them

* Feature: New exchange: Binance Futures
* Feature: New Exchange: Binance Jersey
* Feature: Funding data on Kraken Futures
* Feature: User defined pair separator (default still -)
* Feature: Postgres backend
* Feature: Deribit Funding
* Bugfix: Deribit subscriptions using config subscribed to symbols incorrectly
* Bugfix: Some RabbitMQ messages were missing symbol and exchange data
* Feature: Open interest data for OKX swaps

* Feature: User enabled logging of exchange messages on error
* Refactor: Overhaul of backends - new base classes and simplified code
* Bugfix: Handle i messages from poloniex more correctly
* Bugfix: Report bittrex errors correctly
* Feature: New exchange: Bitcoin.com
* Feature: New exchange: BinanceUS
* Feature: New exchange: Bitmax
* Feature: Ability to store raw messages from exchanges

* Feature: Backfill Bitmex historical trade data from S3 Bucket
* Feature: RabbitMQ backend
* Feature: Custom Depth and deltas for all L2 book updates
* Feature: Support new 100ms book diff channel on Binance
* Feature: Bittrex exchange support
* Feature: Ticker support in Redis and Kafka Backends
* Feature: Ticker callbacks require/contain timestamp
* Feature: Renko Aggregation
* Bugfix: Max Depth without deltas should only send updates when book changes
* Bugfix: Update count and previous book now associated with pair

* Bugfix 113: Fix remaining exchanges who are not reporting timestamps correctly
* Feature: Generated timestamps now based on message receipt by feedhandler
* Feature: Multi-callback support
* Feature: Rework ZMQ using pub/sub with topics
* Feature: FTX Exchange
* Feature: Gemini subscriptions now work like all other exchanges
* Feature: Use unique id for each feed (as opposed to feed id/name)
* Bugfix: fix Poloniex historical trade timestamps
* Bugfix: Bitmex L2 channel incorrectly classified
* Feature: Kraken Futures
* Feature: Redis backend supports UDS
* Feature: Binance full book (L2) with deltas
* Feature: Allow user to start event loop themselves (potentially scheduling other tasks before/after).

* Feature: Rest Endpoints for Historical Deribit data
* Feature: Specify numeric datatype for InfluxDB
* Bugfix: Greatly improve performance of book writes for InfluxDB
* Feature: Bybit exchange support
* Bugfix: Deribit now returning floats in decimal.Decimal
* Feature: Elastic Search backend