HEROLABS/herolabs-apns — pull request #1 by brunchboy (2012-09-25 22:08:43+00:00)
Title: Allow sending the default sound

I was having trouble figuring out why I could not get the default sound to play when pushing alerts using herolabs-apns, and found that the library is currently stripping out any attempts (via `with-sound`) to send a value of "default."

There is a difference between having a `sound` value of `default` and having no `sound` value at all. The latter leads to a silent alert, while the former is Apple's preferred way of requesting the standard notification sound. Per the Apple Push Notification Service Programming Guide, Table 2-1 on Page 20:

> The Name of a sound file in the application bundle. The sound in this file is played as an alert. If the sound file doesn’t exist or `default` is specified as the value, the default alert sound is played. The audio must be in…

Since this is a file name, I thought it would be best to convert any keywords to strings, although you may do that elsewhere in the library anyway.