[New Example] 500pxgram updates

- addressed all comments in PR except autolayout of UIKit code

examples/ASDKgram/Sample/ImageURLModel.h

@@ -6,9 +6,6 @@
 //  Copyright © 2016 Hannah Troisi. All rights reserved.
 //
 
-#import <Foundation/Foundation.h>
-#import <UIKit/UIKit.h>
-
 @interface ImageURLModel : NSObject
 
 + (NSString *)imageParameterForClosestImageSize:(CGSize)size;