* 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
* Attempts to update orderbook so it doesn't need to sort
* Reverts the ws ob stuff. Gets rid of sorting because it happens later. Adds some exchange features
* update existing feature lists. Expands list definition to match my emotions
* Adds bithumb bitmex and bitstamp. adds a couple more types
* Features for you, features for me, features for bittrex, btcmarkets, btse, coinbasepro, coinut, exmo, gateio and gemini
* Features for hitbtc, huobi, itbit, kraken, lakebtc, lbank, localbitcoins, okcoin, okex, poloniex, yobit, zb
* Who can forget good old alphapoint?
* Adds btcmarksets websocket :glitch_crab: fixes alphapoint features
* Adds extra data not in the documentation :/
* Replaces websocket features by using protocol features. However, it breaks it due to import cycles. I'm not sure what I'll do just yet
* Removes import cycle via duplicate structs.
* Increases coverage of config with `TestCheckCurrencyConfigValues`. Moves all currency pair package types into their own files or places it at the bottom of files if necessary
* Increase coverage in code.go
* One way of determining a test has failed, is when to it fails. Removed redundant explanation
* Increases code coverage of conversion
* Lint fixes
* Fixes orderbook tests
* Re-adds sorting because its important to still have the internal pre-processed orderbook to be representative of a real orderbook
* Secret lints that did not show up via Windows linting
* Adds protocol package to contain exchange features
* Fixes protocol implementation
* Fixes ws tests
* Addresses the following: Removes st-st-stutters in config types, changes GetAvailableForexProviders -> GetSupportedForexProviders, removes errors from tests where error is nil, removes orderbook setup when not necessary, removes import newlines, removes false bools from declaration, changes should of to should have
* imports and casing
* Fixes two more nil error checks
