exchanges/bittrex,kucoin: Remove exchange implementation and fix minor test issue (#1403)

* exchanges/Bittrex: Remove exchange implementation

* Kucoin: Fix TestProcessMarketSnapshot after pair removal update

* Kucoin: Fix race due to duplicate setupWS call

Unleash your inner Max Verstappen

* Kucoin: Actually test spot/margin market snapshot replication

docs/ADD_NEW_EXCHANGE.md

@@ -202,7 +202,6 @@ Yes means supported, No means not yet implemented and NA means protocol unsuppor
 | Bithumb | Yes  | NA       | NA  |
 | BitMEX | Yes | Yes | NA |
 | Bitstamp | Yes  | Yes       | No  |
-| Bittrex | Yes | Yes | NA |
 | BTCMarkets | Yes | No       | NA  |
 | BTSE | Yes | Yes | NA |
 | COINUT | Yes | Yes | NA |
@@ -233,7 +232,6 @@ var Exchanges = []string{
 	"bithumb",
 	"bitmex",
 	"bitstamp",
-	"bittrex",
 	"btc markets",
 	"btse",
 	"coinbasepro",

docs/MULTICHAIN_TRANSFER_SUPPORT.md

@@ -50,7 +50,6 @@ $ ./gctcli withdrawcryptofunds --exchange=binance --currency=USDT --address=TJU9
 | Bithumb | No | No | |
 | BitMEX | No | No | Supports BTC only |
 | Bitstamp | No | No | |
-| Bittrex | No | No | NA |
 | BTCMarkets | No | No| NA  |
 | BTSE | No | No | Only through website |
 | Bybit | Yes | Yes | |

docs/OHLCV.md

@@ -73,7 +73,6 @@ A helper tool [cmd/dbseed](../cmd/dbseed/README.md) has been created for assisti
 | Bitmex         |             |        
 | Bitstamp       | Y           | 
 | BTC Markets    | Y           | 
-| Bittrex        |             | 
 | BTSE           | Y           |      
 | Bybit          | Y           | 
 | Coinbase Pro   | Y           |