Load and store URLPreviewViewData in RoomBubbleCellData.

Implement close button and store the action in Core Data. Hide the preview image view when no image is received. Remove line breaks in description text.

Riot/Modules/Room/CellData/RoomBubbleCellData.h

@@ -15,6 +15,9 @@
  */
 
 #import <MatrixKit/MatrixKit.h>
+@class URLPreviewViewData;
+
+extern NSString *const URLPreviewDidUpdateNotification;
 
 // Custom tags for MXKRoomBubbleCellDataStoring.tag
 typedef NS_ENUM(NSInteger, RoomBubbleCellDataTag)
@@ -81,7 +84,7 @@ typedef NS_ENUM(NSInteger, RoomBubbleCellDataTag)
 /**
  A link if the textMessage contains one, otherwise nil.
  */
-@property (nonatomic) NSURL *link;
+@property (nonatomic) URLPreviewViewData *urlPreviewData;
 
 /**
  MXKeyVerification object associated to key verification event when using key verification by direct message.