Group Details: Handle the item selection in rooms and users list.

- Open a contact details screen when the user selects a group member
- Open the room history or a room preview in case of room selection

Riot/ViewController/RoomViewController.h

@@ -57,6 +57,12 @@
  */
 @property (nonatomic, readonly) RoomPreviewData *roomPreviewData;
 
+/**
+ Tell whether a badge must be added next to the chevron (back button) showing number of unread rooms.
+ YES by default.
+ */
+@property (nonatomic) BOOL showMissedDiscussionsBadge;
+
 /**
  Display the preview of a room that is unknown for the user.