Move ffmpeg comment out of the module doc
Update the lastseq with every segment save

- The lastseq attribute was not being updated meaning the
  the missed count was never updated either, this fixes it
Reduce sleep time by half

- I've been seeing some segment loss for large segment (e.g. 20s)
  so I am reducing the waittime to half of the target duration.
- According to the RFC this is actually the default refresh time
  anyway
Fix playlist retry counter

- The playlist fail count was broken causing us to perpetually
  retry fetching the playlist, this commit fixes that.
Minor fix to ffmpeg comment