Use errcheck to find unhandled errors (#795)

Signed-off-by: Chris Cummer <chriscummer@me.com>

modules/cryptoexchanges/bittrex/display.go

@@ -44,7 +44,7 @@ func (widget *Widget) content() (string, string, bool) {
 					formatableText("Open Sell", "OpenSellOrders"),
 			)
 
-			strTemplate.Execute(writer, map[string]string{
+			err := strTemplate.Execute(writer, map[string]string{
 				"nameColor":      widget.settings.colors.market.name,
 				"fieldColor":     widget.settings.colors.market.field,
 				"valueColor":     widget.settings.colors.market.value,
@@ -57,7 +57,11 @@ func (widget *Widget) content() (string, string, bool) {
 				"OpenSellOrders": marketCurrency.OpenSellOrders,
 			})
 
-			str += writer.String() + "\n"
+			if err != nil {
+				str = err.Error()
+			} else {
+				str += writer.String() + "\n"
+			}
 		}
 
 	}

modules/cryptoexchanges/bittrex/widget.go

@@ -90,7 +90,9 @@ func (widget *Widget) Refresh() {
 func (widget *Widget) updateSummary() {
 	// In case if anything bad happened!
 	defer func() {
-		recover()
+		if r := recover(); r != nil {
+			fmt.Println("recovered in updateSummary()", r)
+		}
 	}()
 
 	client := &http.Client{
@@ -120,10 +122,14 @@ func (widget *Widget) updateSummary() {
 				errorText = ""
 			}
 
-			defer response.Body.Close()
+			defer func() { _ = response.Body.Close() }()
 			jsonResponse := summaryResponse{}
 			decoder := json.NewDecoder(response.Body)
-			decoder.Decode(&jsonResponse)
+			err = decoder.Decode(&jsonResponse)
+			if err != nil {
+				errorText = "Could not parse JSON!"
+				break
+			}
 
 			if !jsonResponse.Success {
 				ok = false