Fix bug where left = 0 would be converted to Infinity
Fix bug where left = 0 would be converted to Infinity

Possibly fixes: https://github.com/feross/bittorrent-tracker/issues/196

jhiesey/bittorrent-tracker,LinusU/bittorrent-tracker,feross/bittorrent-tracker,feross/bittorrent-tracker,jhiesey/bittorrent-tracker