Add track weights

src/main.gd

@@ -52,7 +52,18 @@ func _get_track():
 	if _tracks.size() == 0:
 		return null
 	
-	return _tracks.pick_random()
+	var weight = _tracks.reduce(func(accum, track): return accum + (track.weight if track.has("weight") else 1), 0)
+	
+	var rand = randf() * weight
+	var current_weight = 0
+	
+	for track in _tracks:
+		current_weight += track.weight if track.has("weight") else 1
+		
+		if current_weight >= rand:
+			return track
+	
+	return null