Python-libtorrent

* updated to boost 1.64
* lt:fix race condition in disk I/O storage class
* lt:avoid extra sha1_hash memory copy in create_torrent
* lt:fix http connection timeout on multi-homed hosts
* lt:implemented multi-home support
* lt:make DHT bootstrapping more robust by not throwing away nodes
* lt:need_save_resume_data() will no longer return true every 15 minutes
* lt:create a separate DHT node for each listen socket
* lt:avoid connections to trackers when the event is stopped and
stop_tracker_timeout <= 0
* lt:fix storage destruction order issue
* lt:fix memory leak in the disk cache
* lt:magnet links: unescape hash parameter
* lt:fix double free in disk cache
* lt:fix typo in natpmp::start
* lt:remove mutex-release hack in file_pool
* lt:source code cleanup and stability

* fixed synchronization issues in SessionManagerstop

* added support for ip_notifier in macOS
* added resolver_cache_timeout setting for internal host name resolver
* improved public API
* internal fixes in libtorrent

* start of changelog


See ChangeLog

* removed (broken) support for incoming connections over socks5
* restore announce_entry's timestamp fields to posix time in python binding
* deprecate torrent_added_alert (in favor of add_torrent_alert)
* fix python binding for parse_magnet_uri
* fix minor robustness issue in DHT bootstrap logic
* fix issue where torrent_status::num_seeds could be negative
* document deprecation of dynamic loading/unloading of torrents
* include user-agent in tracker announces in anonymous_mode for private torrents
* add support for IPv6 peers from udp trackers
* correctly URL encode the IPv6 argument to trackers
* fix default file pool size on windows
* fix bug where settings_pack::file_pool_size setting was not being honored
* add feature to periodically close files (to make windows clear disk cache)
* fix bug in torrent_handle::file_status
* fix issue with peers not updated on metadata from magnet links

* default TOS marking to 0x20
* fix invalid access when leaving seed-mode with outstanding hash jobs
* fix ABI compatibility issue introduced with preformatted entry type
* add web_seed_name_lookup_retry to session_settings
* slightly improve proxy settings backwards compatibility
* add function to get default settings
* updating super seeding would include the torrent in state_update_alert
* fix issue where num_seeds could be greater than num_peers in torrent_status
* finished non-seed torrents can also be in super-seeding mode
* fix issue related to unloading torrents
* fixed finished-time calculation
* add missing min_memory_usage() and high_performance_seed() settings presets to python
* fix stat cache issue that sometimes would produce incorrect resume data
* storage optimization to peer classes
* fix torrent name in alerts of builds with deprecated functions
* make torrent_info::is_valid() return false if torrent failed to load
* fix per-torrent rate limits for >256 peer classes
* don't load user_agent and peer_fingerprint from session_state
* fix file rename issue with name prefix matching torrent name
* fix division by zero when setting tick_interval > 1000
* fix move_storage() to its own directory (would delete the files)
* fix socks5 support for UDP
* add setting urlseed_max_request_bytes to handle large web seed requests
* fix python build with CC/CXX environment
* add trackers from add_torrent_params/magnet links to separate tiers
* fix resumedata check issue with files with priority 0
* deprecated mmap_cache feature
* add utility function for generating peer ID fingerprint
* fix bug in last-seen-complete
* remove file size limit in torrent_info filename constructor
* fix tail-padding for last file in create_torrent
* don't send user-agent in metadata http downloads or UPnP requests when
in anonymous mode
* fix internal resolve links lookup for mutable torrents
* hint DHT bootstrap nodes of actual bootstrap request