Add delete encrypted files and fix some crashes

utils.go

@@ -0,0 +1,27 @@
+package wiiudownloader
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func isThisDecryptedFile(path string) bool {
+	return strings.Contains(path, "code") || strings.Contains(path, "content") || strings.Contains(path, "meta")
+}
+
+func doDeleteEncryptedContents(path string) error {
+	err := filepath.Walk(path, func(filePath string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.Mode().IsRegular() && !isThisDecryptedFile(filePath) {
+			if err := os.Remove(filePath); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+
+	return err
+}