watcher.go
func (w *Watcher) Watching() (paths []string) {
	paths = make([]string, 0)
	for path, _ := range w.paths {
		paths = append(paths, path)
	}
	return
}
func (w *Watcher) Watching() (paths []string) {
	paths = make([]string, 0)
	for path, _ := range w.paths {
		paths = append(paths, path)
	}
	return
}
// Watching returns a list of the files being watched.