Change "Incomplete/temp folder" term with "download folder".
Allow to set "download folder" per torrent (in manual mode) and per category (in automatic mode).
Define "torrent ID" concept, which is either a SHA1 hash for torrents of version 1,
or a SHA256 hash (truncated to SHA1 hash length) for torrents of version 2.
Add support for native libtorrent2 info hashes.
Originally, it was just a wrapper for libtorrent::torrent_handle class, so it mimicked its name.
It was then transformed into a more complex aggregate, but the name was retained (just by inertia).
Unlike libtorrent::torrent_handle class in whose name "handle" means the pattern used,
it does not matter for qBittorrent classes and just eats up space in the source code.
Normalize Web API method names.
Allow to use alternative Web UI.
Switch Web API version to standard form (i.e. "2.0").
Improve Web UI translation code.
Retranslate changed files.
Add Web API for RSS subsystem.