v5.4.2

Main Changes to previous release version:

Update native carrier lib.

• Support persistent group with the following characteristics:
  1). The peer, already as a member of the group, will automatically be in the group when it come back to be connected from offline state with the notification of "peer listed changed";
  2). The number of the peers in group would include the peers being offline;
  3). The group is totally decentralized-oriented currently without any group management involved;
  4). The peer would miss the group messages when it is being offline state.
• Add to support notification of friend request with different greeting message.