Libtorrent

* made the session disable file name checks within the boost.filesystem library
* fixed race condition in the sockets
* strings that are invalid utf-8 strings are now decoded with the
local codepage on windows
* added the ability to build libtorrent both as a shared library
* client_test can now monitor a directory for torrent files and automatically
start and stop downloads while running
* fixed problem with file_size() when building on windows with unicode support
* added a new torrent state, allocating
* added a new alert, metadata_failed_alert
* changed the interface to session::add_torrent for some speed optimizations.
* greatly improved the command line control of the example client_test.
* fixed bug where upload rate limit was not being applied.
* files that are being checked will no longer stall files that don't need
checking.
* changed the way libtorrent identifies support for its excentions
to look for 'ext' at the end of the peer-id.
* improved performance by adding a circle buffer for the send buffer.
* fixed bugs in the http tracker connection when using an http proxy.
* fixed problem with storage's file pool when creating torrents and then
starting to seed them.
* hard limit on remote request queue and timeout on requests (a timeout
triggers rerequests). This makes libtorrent work much better with
"broken" clients like BitComet which may ignore requests.

* multitracker support
* serves multiple torrents on a single port and a single thread
* supports http proxies and proxy authentication
* gzipped tracker-responses
* block level piece picker
* queues torrents for file check, instead of checking all of them in parallel
* uses separate threads for checking files and for main downloader
* upload and download rate limits
* piece-wise, unordered, incremental file allocation
* fast resume support
* supports files > 2 gigabytes
* supports the no_peer_id=1 extension
* support for udp-tracker protocol
* number of connections limit
* delays sending have messages
* can resume pieces downloaded in any order
* adjusts the length of the request queue depending on download rate
* supports compact=1
* selective downloading
* ip filter