change DownloadDataSender to DLDataConverter and remove UnifiedInterface::initConnection
修复断网续传导致的下载文件错误，已将断网续传功能单独移至PointTask模块，其他后端有自己的断网续传功能，同时修复了悬浮窗在5.3下阴影不显示问题
fix some big file could not rename after download finish
fix httpdownload error and rename bug