聊天会话功能扩展

参考官网写的直接使用 EaseMessageViewController，通过 EaseMessageViewControllerDelegate 和 EaseMessageViewControllerDataSource 两个协议实现对 EaseMessageViewController 的扩展。
 
最好的回话列表中内容没了，用户名和时间还在的
CODE:
EaseMessageViewController *chatController = [[EaseMessageViewController alloc] initWithConversationChatter:@“8001” conversationType:EMConversationTypeChat];
    chatController.delegate = self;
  [self.navigationController pushViewController:chatController animated:YES];