Added test and additional fix for https://github.com/racker/node-tryfer/pull/16

Added a test to ensure no regressions happen.  Discovered an additional bug that may cause problems, namely that [`scribe.Scribe.send`](https://github.com/Applifier/node-scribe/blob/master/lib/scribe.js#L196) is not an asynchronous function - it does not take a callback.

[async.waterfall](https://github.com/caolan/async#waterfalltasks-callback) requires that each function accept a callback, and cannot move on to the next task (or finish) if not callbacked.

So wrapped the call to `scribe.Scribe.send` in a function that takes a callback, and calls it immediately after send.  From looking at the scribe code it doesn't seem like it can error?  And it should return immediately.