* Add new methods:
* `pause`, `unpause`, `toggle_pause`: : Pause/Resume download queue.
* `stop_all_downloads`: Abort all running downloads.
* `restart_failed`: Restart all failed files.
* `toggle_reconnect`: Toggle reconnect activation
* `delete_finished`: Delete all finished files and completly finished packages.
* `restart`: Restart pyload core.
* `free_space`: Get available free space at download directory in bytes.
* Add pytest unit testing for login method
* Refactored `get_status` and `version` methods