Register remote players in the client's IQNet array when their
AddPlayerPacket arrives, so they appear in the Tab player list.
Previously only the host and local player were registered.
Also filter the dedicated server's phantom host entry (slot 0, empty
gamertag) from the UI, fix tick() to update entries by smallId instead
of sequential index, and fix player removal to use gamertag matching
since XUIDs are 0 on dedicated servers.
6a21637e75