Added name of the file with camera roll pictures

Summary:
Added name parameter when delivering the camera roll images using react native CameraRoll library. Based on http://stackoverflow.com/questions/37283976/react-native-get-photo-name-from-camera-roll-ios
Closes https://github.com/facebook/react-native/pull/9961

Differential Revision: D3883582

Pulled By: majak

fbshipit-source-id: 5bfd1eb0601b3ce2ef1cdb4485060661d2fbad32

RCTCameraRollManager.m

@@ -185,12 +185,14 @@ RCT_EXPORT_METHOD(getPhotos:(NSDictionary *)params
           CGSize dimensions = [result defaultRepresentation].dimensions;
           CLLocation *loc = [result valueForProperty:ALAssetPropertyLocation];
           NSDate *date = [result valueForProperty:ALAssetPropertyDate];
+          NSString *filename = [result defaultRepresentation].filename;
           [assets addObject:@{
             @"node": @{
               @"type": [result valueForProperty:ALAssetPropertyType],
               @"group_name": [group valueForProperty:ALAssetsGroupPropertyName],
               @"image": @{
                 @"uri": uri,
+                @"filename" : filename,
                 @"height": @(dimensions.height),
                 @"width": @(dimensions.width),
                 @"isStored": @YES,