Improvements: Added handling existance of files. Colored report output on program ends, halts, or terminating.
    * If video or subtitles file exists, then file don't downloaded again.
    * If after posting data to API method returned answer with "not created" status, then downloader does not stop downloading files.
       * Only inside warningStack array added record about incident. If raised error which differ from defined errors, in this case downloader stops working.
    * Added dependency to new package "color"
    * Added error declarations:
       * FileExistsError
       * EpisodeAlreadyExistsError