Fix providers, fix tests, fix build... (#3826)

* Fix Nyaa

* Mark broken providers

* Set ilCorsaroNero as public

* Remove old KAT cassette

* Disable tests for LimeTorrents, SkyTorrents, ilCorsaroNero

* Disable torrent search test (was using KAT)

* Fix magic_skip

* Fix tox (flake8 not running)

* flake8 first

* flake8: Exclude .tox, fix setup.py

* flake8: Include rather than exclude

* Apply isort to sickbeard (possible breakages!)

* Apply isort to sickrage (possible breakages!)