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.
These files were created and edited in their entirety in commit 8db4bde15d
As far as I can tell they were almost entirety rewritten from their original state.
The old copyright attribution is restored and the new author is added too.
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.
This applies to "About Dialog", "Ban List Options Dialog", "Download From URL Dialog", "IP Subnet
Whitelist Options Dialog", "Search Plugin Select Dialog", "Search Plugin Source Dialog",
"Statistics Dialog", "Speed Limit Dialog" and "Torrent Options Dialog".
Also unifies storing the dialog size under the key "Size".