Adding download zip file, fix local cover art for m4b download

client/plugins/constants.js

@@ -0,0 +1,14 @@
+const DownloadStatus = {
+  PENDING: 0,
+  READY: 1,
+  EXPIRED: 2,
+  FAILED: 3
+}
+
+const Constants = {
+  DownloadStatus
+}
+
+export default ({ app }, inject) => {
+  inject('constants', Constants)
+}