* Update Bittrex API from v1.1 to v3
V1.1 has been retired as of 9/30/2020
- Update REST to V3
- Add initial websocket support
* Bittrex update - enable websockets in testdata config file
* Update Bittrex - add Websocket capability to docs
* Update Bittrex connector
- AppVeyor warnings
- Update tests
- Generate documentation
- Fix nits
* Update Bittrex - add websocket order processing
* Update Bittrex connector
* Bittrex connector - fix ineffectual err assignment
* Fix nits
* Orderbook synchronization
* Remove redundant nil
* Log WS fetch orderbook message as debug message instead of as warning
* Update after rebase
* Add tests
* Add allowed candle interval values
* Replace literals with declared constants
* Replace variable name 'request' with 'req'
* Add check and update for deprecated REST URL
* Nits and some cleaning up
* Change ParseInt bit size to 64
* [FIX] Remove several shadow declarations
* Do not export constructTicker
* Remove parseTime()
* Update GetHistoricCandles()
* [FIX] Address gocritic nits
* [FIX] Address gocritic nits
* Use SendMessageReturnResponse() instead of local map
* Rate limit subscribing and unsubscribing
* [FIX] use go routine for subscribing and unsubscribing
* [FIX] Set correct index for map
* [FIX] Address unused vars, literals, time format
* Adjusted timing when subscribing to many order books
* Cache partial updates to tickers instead of calling REST function
* [FIX] Update sequence nr when multiple updates are queued
* Address golint issues
* Fix nits
* Adds mock testing to ZB
* STEALS improved time validation code from the original STOLEN validation code :D
* Mini fixes from review
* happy fun comment stealing
* Moves the loop checker earlier to ensure no double appendages
* Fixes sneaky test
* Fixes the important part where mock tests work instead of live tests
* Skips authenticated endpoints for mock testing.
* lint
* Updates candle wrapper functions to respect design
* basic linting fix
* Reverts configtest.json, updates readme to be way better, adds coverage to validateCandlesRequest
* Tiniest grammatical fix
* Fixes more outdated code references
* Closing out a high
* Fixes spacing
* Replaces all instances of 4 spaces in tmpl files with a tab
* fixes spacing and tab related readme issues once and for all 🤞
* tidy
* indentation violation identification situation
* Add exchange manager to engine
* Several improvements for engine and friends
1) New file.Exists func
2) gRPC TLS cert expiration date check and regeneration
3) New donation var for use across the codebase
4) Use Go log package until the logger is initialised
* Add cert tests and create dir tree if it doesn't exist for file.Write
* Link up donation address to documentation tool plus minor adjustments
* Fix remaining donation addrs
* Move non-needed reload exchange funcs
* Revert accidental config_example.json changes 🕯️
* Use go logger for logging until the logger has initiliased, otherwise no output will be seen
* Link up portfolio delay val and other fixes
* Run go mod tidy after dependabot PR
* Address nitterinos
