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- adding `user-agent` to request headers now (https://github.com/fracpete/kodi-nfo-generator/pull/6)
- only making IMDB request when `--overwrite` flag present or `.nfo` not present, to avoid making
too many calls to IMDB
- the `--delay` no longer applies when not writing a file
- fixed TV show .nfo generation (https://github.com/fracpete/kodi-nfo-generator/issues/1)
- added `download-missing` choice for downloading fanart only when it is missing locally
(`download` always performs a download)