Fix bug #22628: status orbs wrong in replay if not side 1

This concerns https://gna.org/bugs/index.php?22628

In the replay code, the viewing side was always set to 0 if it was a single player game.

Also, "show_team_" was replaced with the boolean "is_multiplayer_" as there was no reason to use an int in
this case.
The viewing_team_ member variable introduced here isn't included after is_multiplayer_ as part of the initializer list in replay_controller's constructor, but it's set in the constructor body. IIRC this should generate a warning with some compilers -- you should add it to the initializer list since there doesn't seem to be any reason to not do so.