Libtorrent

* requires boost >= 1.58 to build
* tweak heuristic of how to interpret url seeds in multi-file torrents
* support &ipv4= tracker argument for private torrents
* renamed debug_notification to connect_notification
* when updating listen sockets, only post alerts for new ones
* deprecate anonymous_mode_alert
* deprecated force_proxy setting (when set, the proxy is always used)
* add support for Port Control Protocol (PCP)
* deliver notification of alerts being dropped via alerts_dropped_alert
* deprecated alert::progress_notification alert category, split into
finer grained categories
* update plugin interface functions for improved type-safety
* implemented support magnet URI extension, select specific file indices
for download, BEP53
* make tracker keys multi-homed. remove set_key() function on session.
* add flags()/set_flags()/unset_flags() to torrent_handle, deprecate individual functions
* added alert for block being sent to the send buffer
* drop support for windows compilers without std::wstring
* implemented support for DHT info hash indexing, BEP51
* removed deprecated support for file_base in file_storage
* added support for running separate DHT nodes on each network interface
* added support for establishing UTP connections on any network interface
* added support for sending tracker announces on every network interface
* introduce "lt" namespace alias
* need_save_resume_data() will no longer return true every 15 minutes
* make the file_status interface explicitly public types
* added resolver_cache_timeout setting for internal host name resolver
* make parse_magnet_uri take a string_view instead of std::string
* deprecate add_torrent_params::url field. use parse_magnet_uri instead
* optimize download queue management
* deprecated (undocumented) file:// urls
* add limit for number of web seed connections
* added support for retrieval of DHT live nodes
* complete UNC path support
* add packets pool allocator
* remove disk buffer pool allocator
* fix last_upload and last_download overflow after 9 hours in past
* python binding add more add_torrent_params fields and an invalid key check
* introduce introduce distinct types for peer_class_t, piece_index_t and
file_index_t.
* fix crash caused by empty bitfield
* removed disk-access-log build configuration
* removed mmap_cache feature
* strengthened type safety in handling of piece and file indices
* deprecate identify_client() and fingerprint type
* make sequence number for mutable DHT items backed by std::int64_t
* tweaked storage_interface to have stronger type safety
* deprecate relative times in torrent_status, replaced by std::chrono::time_point
* refactor in alert types to use more const fields and more clear API
* changed session_stats_alert counters type to signed (std::int64_t)
* remove torrent eviction/ghost torrent feature
* include target in DHT lookups, when queried from the session
* improve support for HTTP redirects for web seeds
* use string_view in entry interface
* deprecate "send_stats" property on trackers (since lt_tracker extension has
been removed)
* remove deprecate session_settings API (use settings_pack instead)
* improve file layout optimization when creating torrents with padfiles
* remove remote_dl_rate feature
* source code migration from boost::shared_ptr to std::shared_ptr
* storage_interface API changed to use span and references
* changes in public API to work with std::shared_ptr<torrent_info>
* extensions API changed to use span and std::shared_ptr
* plugin API changed to handle DHT requests using string_view
* removed support for lt_trackers and metadata_transfer extensions
(pre-dating ut_metadata)
* support windows' CryptoAPI for SHA-1
* separated ssl and crypto options in build
* remove lazy-bitfield feature
* simplified suggest-read-cache feature to not depend on disk threads
* removed option to disable contiguous receive buffers
* deprecated public to_hex() and from_hex() functions
* separated address and port fields in listen alerts
* added support for parsing new x.pe parameter from BEP 9
* peer_blocked_alert now derives from peer_alert
* transitioned exception types to system_error
* made alerts move-only
* move files one-by-one when moving storage for a torrent
* removed RSS support
* removed feature to resolve country for peers
* added support for BEP 32, "IPv6 extension for DHT"
* overhauled listen socket and UDP socket handling, improving multi-home
support and bind-to-device
* resume data is now communicated via add_torrent_params objects
* added new read_resume_data()/write_resume_data functions to write bencoded,
backwards compatible resume files
* removed deprecated fields from add_torrent_params
* deprecate "resume_data" field in add_torrent_params
* improved support for bind-to-device
* deprecated ssl_listen, SSL sockets are specified in listen_interfaces now
* improved support for listening on multiple sockets and interfaces
* resume data no longer has timestamps of files
* require C++11 to build libtorrent

* replace use of boost-endian with boost-predef

* using android NDK r18b
* updated to boost 1.69.0
* updated to OpenSSL 1.1.1a
* fixed activeDhtLimit SettingsPack setter
* development: new local build scripts for macosx, android, linux, windows
* lt:only allow cwnd to be reduced so often (utp)
* lt:avoid announcing local ip to private tracker
* lt:don't treat loss of MTU probe packet as a congestion signal (utp)
* lt:make sure we reset the duplicate ack counter every time we don't receive
a duplicate ack (utp)
* lt:remove old (incompatible) sequence number build option (utp)
* lt:don't leave slow-start just because we hit the advertized receive window
* lt:simplify and improve the uTP deferred ACK logic to respond earlier
* lt:improve logic for fast-retransmitting packets on incoming SACK
* lt:improve utp verbose logging a bit and make the parser pull out more
metrics
* lt:restore permissions on directories to 1.1. i.e. rely on umask
* lt:minor fix to invalid_request_alert logging
* lt:add assignment operator to span
* lt:fix %u -> %d format codes
* lt:fix deprecation markup in torrent_status
* lt:tweak heuristic of how to interpret url seeds in multi-file torrents
* lt:added more TORRENT_DEPRECATED_ENUM and deprecated unused aio_max in
settings_pack
* lt:take a string_view in setting_by_name
* lt:fix typo in peer log
* lt:deprecate start_default_features flag, it's only used in deprecated API
* lt:remove verbose peer logging
* lt:make stack_allocator::format_string() grow the buffer for large strings
* lt:move where socket buffers are set up, to happen after the socket is
opened. log errors in the peer's log instead of session and torrent
* lt:add stats counter for the number of outstanding async_accept calls
* lt:fix potential issue where the dht port message is sent before the peer
handshake
* lt:correct %u format code for pieces in printf() calls
* lt:attempt to fix an assert for a newly connected peer that disconnects just
as we receive the metadata
* lt:don't use page aligned disk buffers
* lt:include &ipv4= for private trackers
* lt:add support for &ipv4= tracker argument
* lt:use new bdecoder in ut_metadata class
* lt:fix redundant bytes overflow
* lt:check for self-assignment in bitfield operator=
* lt:initialize bencoded ints with zero when constructed
* lt:exit natpmp::on_reply earlier if we're shutting down
* lt:fix setting ipv6 interface
* lt:a better fix to the ssl port announce bug
* lt:perfect forward async handlers for udp_socket to underlying asio socket
* lt:move the whole add_torrent_params object into save_resume_data_alert
* lt:actually fix the issue with the second tracker announce with port 0
* lt:remove redundant MTU boundary checks
* lt:fix of asio-debugging build in natpmp. resend_request could be called
directly, not only as a handler for an async operation
* lt:fix move_storage with save_path with a trailing slash
* lt:only make snubbed peers invert the piece picking strategy when we're
doing rarest first
* lt:ssl listen port fix and improved tracker announce logging
* lt:properly tear down the disk_io_thread object in set_piece_hashes() when
exiting via an exception
* lt:make throwing versions of read_resume_data
* lt:fix overflow in sliding_average in the case of very high download rates
* lt:renamed debug_notification to connect_notification
* lt:fix issue in udp_socket with unusual socket failure
* lt:utp close-reason use after free fix
* lt:source code cleanup, performance and stability

* uTP performance fixes

* fix move_storage with save_path with a trailing slash
* fix tracker announce issue, advertising port 0 in secondary IPv6 announce
* fix missing boost/noncopyable.hpp includes
* fix python binding for torrent_info::creation_date()

* fix issue in udp_socket with unusual socket failure
* split progress_notification alert category into file-, piece- and block progress
* utp close-reason fix
* exposed default add_torrent_params flags to python bindings
* fix redundant flushes of partfile metadata
* add option to ignore min-interval from trackers on force-reannounce
* raise default setting for active_limit
* fall back to copy+remove if rename_file fails
* improve handling of filesystems not supporting fallocate()
* force-proxy no longer disables DHT
* improve connect-boost feature, to make new torrents quickly connect peers

* save both file and piece priorities in resume file
* added missing stats_metric python binding
* uTP connections are no longer exempt from rate limits by default
* fix exporting files from partfile while seeding
* fix potential deadlock on Windows, caused by performing restricted
tasks from within DllMain
* fix issue when subsequent file priority updates cause torrent to stop