Add KVO to collection view controller
Add KVO to collection view controller

lerosua/CTAssetsPickerController,novixon/CTAssetsPickerController,eleven-huang/CTAssetsPickerController,lerosua/CTAssetsPickerController,rokaka/CTAssetsPickerController,pcompassion/CTAssetsPickerController,novixon/CTAssetsPickerController,eleven-huang/CTAssetsPickerController,rokaka/CTAssetsPickerController