Changed look of song loading, fix custom game assets and song skins, fix auth error

- Change the way a selected song appears while it is loading the metadata
- Fix custom taikowebskin
- Fix importing custom game assets (local only)
- Get the oauth token again on auth error

public/src/js/customsongs.js

@@ -136,10 +136,12 @@ class CustomSongs{
 		}
 	}
 	songsLoaded(songs){
-		var length = songs.length
-		assets.songs = songs
-		assets.customSongs = true
-		assets.customSelected = 0
+		if(songs){
+			var length = songs.length
+			assets.songs = songs
+			assets.customSongs = true
+			assets.customSelected = 0
+		}
 		assets.sounds["se_don"].play()
 		this.clean()
 		setTimeout(() => {