fix gdax exchange class

Author: timkpaine

algocoin/lib/exchanges/gdax.py

@@ -168,3 +168,9 @@ def sell(self, req: TradeRequest) -> TradeResponse:
                              remaining=float(order.get('remaining_amount', 0.0)),
                              )
         return resp
+
+    def cancel(self, resp: TradeResponse):
+        raise NotImplementedError()
+
+    def cancelAll(self, resp: TradeResponse):
+        raise NotImplementedError()