Logging and Seeding

This PR is for two issues:

NOW-256 - logging
NOW-265 - seeding
Should we consider a truncate-logs task as well? In production, when the log files become large it's often a good idea to rotate them/copy them/back them up and truncate them _without_ server restart (nginx does this well). Maybe we should provide a wrapper to [truncate](http://nodejs.org/api/fs.html#fs_fs_truncate_path_len_callback)? Not sure if we want to consider doing this at all or consider it as a part of this ticket.