iOS9 Background Location Support

[johnnyshankman]

Currently we cannot do background location updates with SOMotionDetector on iOS9

We have to expose a way to set the allowsBackgroundLocationUpdates property of the SOLocationManager's instance of CLLocationManager to YES or NO.

https://developer.apple.com/library/prerelease/ios/releasenotes/General/iOS90APIDiffs/Objective-C/CoreLocation.html

https://developer.apple.com/library/prerelease/ios/documentation/CoreLocation/Reference/CLLocationManager_Class/index.html#//apple_ref/occ/instp/CLLocationManager/allowsBackgroundLocationUpdates

[johnnyshankman]

I currently do this to get around it. Maybe I'll make a pull request.

In SOMotionDetector:

- (void)updateLocationInBackgroundMode {
    [[SOLocationManager sharedInstance] setBackgroundUpdates: true];
}

In SOLocationManager:

- (void)setBackgroundUpdates:(bool)shouldUpdate {
    self.locationManager.allowsBackgroundLocationUpdates = shouldUpdate;
}

That way the dev makes once call to [[SOMotionDetector sharedInstance] updateLocationInBackgroundMode]] before starting updates and they are good to go.