This class will watch a directory or a set of directories and alert you of new files, modified files, deleted files.
Author: Paul Horman, paulhorman.com/filesystemwatcher/ Author: Alex Chaffee
TODO: make it notice deleted files natively, rather than passing to 'examine' TODO: use github.com/spicycode/fsevent
todo: make sure this works in non-Mac environments (also Macs without growlnotify)