Refactored video files to be mime typed by built-in module mimetypes, no longer requires end-user to specify allowed video file extensions
Fixed issues with custom Newznab providers and saving settings

added code to migrate series provider default language from 2-code to 3-code

fixed "string indices must be integers" when attempting to retrieve season images from series providers

fixed "'NoneType' object is not iterable" when retrieving languages from series provider
added retry count of 3 for SiCKRAGE oauth2 token refreshes

fixed "string indices must be integers" when attempting to retrieve series provider season images
fixed "cannot serialize (type int)" when attempting to write series metadata nfo

switched anonymous referrer to anonym.to
fixed local variable 'refresh_token' referenced before assignment in cache offline token migration