Feature: Add support to check whether an exchange supports automatic currency pair updates and if they don't, show a warning if the last currency pair update is >= 30 days

Also fix race condition in config get/set functions

exchanges/okcoin/okcoin.go

@@ -98,6 +98,7 @@ func (o *OKCoin) SetDefaults() {
 	o.RESTPollingDelay = 10
 	o.FuturesValues = []string{"this_week", "next_week", "quarter"}
 	o.AssetTypes = []string{ticker.Spot}
+	o.SupportsAutoPairUpdating = false
 
 	if okcoinDefaultsSet {
 		o.AssetTypes = append(o.AssetTypes, o.FuturesValues...)
@@ -136,6 +137,10 @@ func (o *OKCoin) Setup(exch config.ExchangeConfig) {
 		if err != nil {
 			log.Fatal(err)
 		}
+		err = o.SetAutoPairDefaults()
+		if err != nil {
+			log.Fatal(err)
+		}
 	}
 }