wubloader/downloader
Mike Lang 6d55f01de6 downloader: Fix a bug when we can't find a particular stream quality
The intended behaviour was to log a warning message and retry next time,
but still allow workers to be started for any streams found.

However, due to a missing continue, we fall through to attempting to start a worker
for a non-existent quality which causes a KeyError when looking up
`self.latest_urls[quality]`. This exception means we don't run through the other qualities,
so we never start any other quality.
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downloader downloader: Fix a bug when we can't find a particular stream quality
Dockerfile Add file and make as build dependencies
setup.py downloader: Track timestamp of latest segment