Fixes

* Updated curses downloader to log stacktraces on SIGUSR1
* Fixed bugs where if we start downloading a new magnet link, when we get to the stage of actual downloading
  the download doesn't actually work
* Added refresh method to TorrentDataDelagate object. Not tested yet.
* Fixed bug when handling an exception in sendMessageToPeer
* Improved responsiveness on shutdown:
  * When the caller asks for torrent information when we are already shutting down, we no longer wait on a mutex that will never get signalled
  * Reactor now only waits for pending writes to complete, not also for pending connection attempts to complete