Engine: Protocol Features, coverage, types, BTC markets websocket (#368)

* 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

config/config_encryption.go

@@ -43,7 +43,7 @@ func (c *Config) PromptForConfigEncryption(configPath string, dryrun bool) bool
 	}
 
 	if !common.YesOrNo(input) {
-		c.EncryptConfig = configFileEncryptionDisabled
+		c.EncryptConfig = fileEncryptionDisabled
 		err := c.SaveConfig(configPath, dryrun)
 		if err != nil {
 			log.Errorf(log.ConfigMgr, "cannot save config %s", err)