Fixes since 1.0.10
* updating super seeding would include the torrent in state_update_alert
* finished non-seed torrents can also be in super-seeding mode
* make torrent_info::is_valid() return false if torrent failed to load
* fix torrent_status time_since_upload/download counters for paused torrents
* fix bug in last-seen-complete
* fix DHT announce stall when adding torrent immediately after startup
* fix bug in enumeration of network interfaces on windows
* fix padfile issue
* fix PMTUd bug
* update puff to fix gzip crash