Notification Sounds do not work on Android in push 3.0

Nobody has claimed this yet.

After a day of testing, and looking through the code, I don't think this works on Android:

Here is the documentation from the [Cordova Plugin](https://github.com/phonegap/phonegap-plugin-push#sound) used by this Meteor package.

```
In order for your your notification to play a custom sound you will need to add the files to your Android project's res/raw directory. Then send the follow JSON from GCM:

{
title:"Sound Test",
message: "Loaded res/raw",
soundname: "test"
}
Note: when you specify the custom sound file name omit the file's extension.
```

Here is where raix:push [wraps and sends the notification](https://github.com/raix/push/blob/c1602dddd9c159d4c8aeb84e53d4118b805f354c/lib/server/push.api.js#L276):

```
if (typeof notification.sound !== 'undefined') {
data.soundname = notification.sound;
}
```

Here is how it's [documented to work](https://github.com/raix/push/blob/1c2e6bcdd62707e800e5dbb34b457e7fbb558fd8/docs/BASIC.md#L62):

``` js
Push.send({
from: 'Test',
title: 'Hello',
text: 'World',
badge: 12,
// sound: fileInPublicFolder
query: {
userId: 'xxxxxxxxxxxx'
}
});
```

All of which don't make sense when put together. It may work on iOS, but on Android, I'm calling it out as broken. **If you've used this on Android, I'd love to know how you got notification sounds to work.**

I'm a newb at Cordova, but from the docs, these would be the steps:

From the cordova plugin docs:

1) In order for your your notification to play a custom sound you will need to add the files to your Android project's `res/raw` directory.
2) Send the notification live above (w/o the file extension)

I don't know how to do 1)

Would love to be wrong about it not working :-)

Start with lib/server/push.api.js around the notification.sound handling and compare it with the Android sound requirements in the linked Cordova plugin documentation. Review docs/BASIC.md and verify how the sound file is expected to reach Android's res/raw directory and how its name is sent; done means the documented flow works for Android or the limitation is clearly documented.

Written by the indexing model from the issue text.