http://gna.org/bugs/?23833
I removed the replay_controller class, instead the normal replay also
uses the mp_replay_controller class which is a 'plugin' to
playsingle_controller which can just be deactivated to switch into
normal gameplay.
Instead of having different exceptions (ai_end_turn_exception,
end_level_exception and restart_turn_exception) we now have one exception
(return_to_play_side_exception) that is used to escape from play_ai_turn
or play_slice and is catched in the play_side related functions.
The information why we returned to play_side is already stored in the
playsingle_controller object. That is also why we do not need the
possible_end_play_signal return value anymore.
play_controller::check_victory does not throw exceptions anymore
Also do_replay and thus turn_info::process_network_data don't throw
exceptions anymore when the scenario is finished by victory or defeat.
Instead it returns REPLAY_FOUND_END_LEVEL, this means
return_to_play_side_exception is not thrown during replay at all.
this also fixed up a previous commit 'refactor play_side' where
accidently play_idle_loop was called instead of play_human_turn in
play_side.
