Bugfix/shutdown after download closing after one download

[CometDog]

• TorrentTaskService will now verify that all torrent downloads are out of the DOWNLOADING state before attempting to shut down the app
• Added the FLAG_ACTIVITY_CLEAR_TOP flag to the intent to launch MainActivity from AddTorrentActivity
  • The behavior without this causes multiple layers of MainActivity to be created, meaning the app won't fully shut down at shut down, it'll just close the top layer. This change fixes that behavior

[proninyaroslav]

Thanks. I don't know why checking downloaded torrents has disappeared.

[CometDog]

It is possible that this seemed to be functional due to the other bug I fixed. Since AddTorrentActivity was creating a new layer of MainActivity every time you added a torrent, after each download finished, only layer would be stripped off. So you had 8 torrents, and 8 layers of MainActivity. After each one, a layer gets removed until the app actually shuts down and closes.