make converter be able to handle multiple requests

Signed-off-by: Ramon Rüttimann <ramon@nine.ch>

main.go

@@ -30,10 +30,8 @@ func main() {
 }
 
 func conversionHandler() http.HandlerFunc {
-	conv := converter.New(iTunesDir)
-
 	return func(w http.ResponseWriter, r *http.Request) {
-		if err := conv.Process(r.Body); err != nil {
+		if err := converter.New(iTunesDir).Process(r.Body); err != nil {
 			klog.Errorf("could not convert: %v", err)
 			fmt.Fprintf(w, "could not convert: %v", err)
 		}