* i2psnark: Improvements for torrents with > 4 leechers:
      choke based on upload rate when seeding, and
      be smarter and fairer about rotating choked peers.
    * Handle two common i2psnark OOM situations rather
      than shutting down the whole thing.
    * Fix reporting to tracker of remaining bytes for
      torrents > 4GB (but ByteMonsoon still has a bug)