server: split out _onRequest() et al
server: split out _onRequest() et al

precisit/bittorrent-tracker,LinusU/bittorrent-tracker,maxogden/bittorrent-tracker,feross/bittorrent-tracker,jhiesey/bittorrent-tracker,feross/bittorrent-tracker,jhiesey/bittorrent-tracker,prozacchiwawa/bittorrent-tracker