Please add polling

[Andrei-Stepanov]

Hello,

Problematic code is:

file-queue/lib/maildir.js

Line 58 in 6f2bfa6

that.watcher = that.fs.watch(that.dirPaths[NEW], {}, function(err, messages) {

      that.watcher = that.fs.watch(that.dirPaths[NEW], {}, function(err, messages) {
        that.emit('new', [messages]);
      });

This code doesn't work for NFS3.

http://docs.libuv.org/en/v1.x/fs_event.html

    UV_FS_EVENT_WATCH_ENTRY = 1,
    /*
    * By default uv_fs_event will try to use a kernel interface such as inotify
    * or kqueue to detect events. This may not work on remote file systems such
    * as NFS mounts. This flag makes fs_event fall back to calling stat() on a
    * regular interval.
    * This flag is currently not implemented yet on any backend.
    */

Please, add polling: say for each 30-60 seconds fs.readdir -> if files are present emit 'new' event.