Transmission-rpc

Features
- **client**: `add_torrent` support `pathlib.Path` ([112](https://github.com/Trim21/transmission-rpc/issues/112))

Code Refactoring
- **client**: add argument type `.change_torrent()` ([114](https://github.com/Trim21/transmission-rpc/issues/114))
- **client**: deprecating relative `Path` as remote path ([113](https://github.com/Trim21/transmission-rpc/issues/113))
- **torrent**: property `error` and `error_string`

Reverts
- refactor(client): add argument type `.change_torrent()` ([114](https://github.com/Trim21/transmission-rpc/issues/114))

BREAKING CHANGE

- `Client`: use relative `pathlib.Path` as remote path for `.move_torrent_data()`, `.locate_torrent_data()`, `.rename_torrent_path()` and `.free_space()` is deprecated.

- `add_torrent`: base64 encoded str as torrent is deprecated, and will be removed in v4

Features
- **session**: add some dict style method like `.key()` and `.items()` ([111](https://github.com/Trim21/transmission-rpc/issues/111))

Features
- add `Session.items()`

Code Refactoring
- add kwargs types for `Client.add_torrent` ([108](https://github.com/Trim21/transmission-rpc/issues/108))

Bug Fixes
- disable proxy from environment variable

Bug Fixes
- **torrent**: `Torrent.date_active` for never activated torrent

Bug Fixes
- make sure `id` is always in `argumenets` ([95](https://github.com/Trim21/transmission-rpc/issues/95))