Save grid view images on orientation change

State of Grid View, including the list of photos, is now saved on screen orientation change ( #4 ) 
 
Classes `Photo`, `Comment`, `PhotoInformation`, and `FlickPhotoLoaderHelper` now implement Parcelable.  

In the main `FlickrViewrFragment`, the `FlickPhotoLoaderHelper` object is saved in `onSaveInstanceState` and restored in the Fragment's `onActivityCreated` function.