Qbittorrent-api

- Replace ``TorrentStates.FORCE_DOWNLOAD='forceDL'`` with ``TorrentStates.FORCED_DOWNLOAD='forcedDL'``

- Generally refactor ``requests.py`` so it's better and easier to read
- Persist a Requests Session between API calls instead of always creating a new one...small perf benefit
- Move auth endpoints back to a dedicated module
- Since ``attrdict`` is apparently going to break in Python 3.10 and it is no longer maintained, I've vendored a modified version (fixes 45)
- Created ``handle_hashes`` decorator to hide the cruft of continuing to support hash and hashes arguments

- Support qBittorrent v4.3.3 and Web API v2.7 (...again)
- New ``torrents/renameFile`` and ``torrents/renameFolder`` endpoints
- Retrieve app api version when needed instead of caching
- Stop verifying and removing individual parameters when they aren't supported

- Support qBittorrent v4.3.2 and Web API v2.7
- ``torrents/add`` supports adding torrents with tags via ``tags`` parameter
- ``app/preferences`` supports toggling internationalized domain name (IDN) support via ``idn_support_enabled``
- BREAKING CHANGE: for ``torrents/add``, ``is_root_folder`` (or ``root_folder``) is superseded by ``content_layout``
- For ``torrents/delete``, ``delete_files`` now defaults to ``False`` instead of required being explicitly passed

- Add support for non-standard API endpoint paths (Fixes 37)
- Allows users to leverage this client when qBittorrent is configured behind a reverse proxy
- For instance, if the Web API is being exposed at "http://localhost/qbt/", then users can instantiate via ``Client(host='localhost/qbt')`` and all API endpoint paths will be prefixed with "/qbt"
- Additionally, the scheme (i.e. http or https) from the user will now be respected as the first choice for which scheme is used to communicate with qBittorrent
- However, users still don't need to even specify a scheme; it'll be automatically determined on the first connection to qBittorrent
- Neither of these should be breaking changes, but if you're instantiating with an incorrect scheme or an irrelevant path, you may need to prevent doing that now

- Support qBittorrent v4.3.1 and Web API v2.6.1
- Path of torrent content now available via ``content_path`` from ``torrents/info``