Error when deploying to IOS8+

I received the error on line 105 of BPXLUUIDHandler.m:

```
return [[UIDevice currentDevice] uniqueIdentifier];
```

To let this work in a simulator, change the code to:

```
NSUUID *identifierForVendor = [[UIDevice currentDevice] identifierForVendor];
return [identifierForVendor UUIDString];
```

That worked for me!
