Added golangci linting and improved what was required

cmd/guimock/main.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 
 	"github.com/hpdvanwyk/invertergui/frontend"
+	"github.com/hpdvanwyk/invertergui/mk2if"
 	"github.com/hpdvanwyk/invertergui/webgui"
 
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -13,7 +14,7 @@ import (
 
 func main() {
 	addr := flag.String("addr", ":8080", "TCP address to listen on.")
-	mk2 := NewMk2Mock()
+	mk2 := mk2if.NewMk2Mock()
 	gui := webgui.NewWebGui(mk2)
 
 	http.Handle("/", frontend.NewStatic())