Instagram-private-api-extensions

Change log:
- live: Changes to fix 5 ([details - potentially breaking changes](https://github.com/ping/instagram_private_api_extensions/issues/5issuecomment-304426574))
* ``downloader.stitch()`` now returns list of generated filenames.
* new downloader attribute ``segment_meta``

Change log:
- live: Prepend init chunk only to first segment in timeline

Change log:
- live: Force download of init segments, skip processing of duplicate mpd

Change log:
- live: Increase ffmpeg loglevel to error
- Add documentation https://instagram-private-api-extensions.readthedocs.io/en/latest/

Change log:
- media: Add save_only bool flag to return only file path and not read vid file into memory for videos
- live: Use max_connection_error_retry for fragment download

Change log:
- media: Update moviepy dependency to 0.2.3.1
- media: Disable progress bar by default for ``prepare_video()``