nlf.find never seems to complete

`nlf.find()` never seems to complete.  i've added a failing test proving this:

```sh
$ make test

  ...

  nlf
    .find()
      1) should work


  16 passing (50 seconds)
  1 failing

  1) nlf .find() should work:
     Error: timeout of 50000ms exceeded
      at null.<anonymous> (/Users/stephenmathieson/work/nlf/node_modules/mocha/lib/runnable.js:139:19)
      at Timer.listOnTimeout [as ontimeout] (timers.js:110:15)

```