use game_data* instead of boost::optional<game_data&> in tod_manager

after updating to boost 1.60 boost have me erros related to
boost::optional<game_data&> in stage_sf_with_rca.cpp where game_data is
not defined (only declared).

Using game_data* solved this problems and also simplies the code by
using simpler datatypes.

src/ai/testing/stage_sf_with_rca.cpp

@@ -278,7 +278,7 @@ void strategy_formulation_with_rca::switch_side()
 	else
 		this->set_side(1);
 
-	resources::tod_manager->next_turn(*resources::gamedata);
+	resources::tod_manager->next_turn(resources::gamedata);
 
 	DBG_AI_TESTING_SF_WITH_RCA << "switch to turn " << resources::tod_manager->turn() << std::endl;
 	DBG_AI_TESTING_SF_WITH_RCA << "------switch_side() end------" << std::endl;

src/game_events/action_wml.cpp

@@ -409,7 +409,7 @@ WML_HANDLER_FUNCTION(modify_turns, /*event_info*/, cfg)
 		if(new_turn_number_u < 1 || (new_turn_number > tod_man.number_of_turns() && tod_man.number_of_turns() != -1)) {
 			ERR_NG << "attempted to change current turn number to one out of range (" << new_turn_number << ")" << std::endl;
 		} else if(new_turn_number_u != current_turn_number) {
-			tod_man.set_turn_by_wml(new_turn_number_u, *resources::gamedata);
+			tod_man.set_turn_by_wml(new_turn_number_u, resources::gamedata);
 			resources::screen->new_turn();
 		}
 	}

src/play_controller.cpp

@@ -1234,7 +1234,7 @@ void play_controller::play_turn()
 
 void play_controller::check_time_over()
 {
-	const bool time_left = gamestate().tod_manager_.next_turn(gamestate().gamedata_);
+	const bool time_left = gamestate().tod_manager_.next_turn(&gamestate().gamedata_);
 
 	if(!time_left) {
 		LOG_NG << "firing time over event...\n";

src/synced_commands.cpp

@@ -549,7 +549,7 @@ SYNCED_COMMAND_HANDLER_FUNCTION(debug_turn, child, use_undo, /*show*/, /*error_h
 
 	debug_notification(":turn debug command was used during turn of $player");
 
-	resources::tod_manager->set_turn(child["turn"].to_int(1), *resources::gamedata);
+	resources::tod_manager->set_turn(child["turn"].to_int(1), resources::gamedata);
 
 	resources::screen->new_turn();
 	resources::screen->redraw_everything();

src/tod_manager.cpp

@@ -410,7 +410,7 @@ void tod_manager::set_number_of_turns_by_wml(int num)
 	update_server_information();
 }
 
-void tod_manager::set_turn(const int num, boost::optional<game_data &> vars, const bool increase_limit_if_needed)
+void tod_manager::set_turn(const int num, game_data* vars, const bool increase_limit_if_needed)
 {
 	const int new_turn = std::max<int>(num, 1);
 	LOG_NG << "changing current turn number from " << turn_ << " to " << new_turn << '\n';
@@ -425,7 +425,7 @@ void tod_manager::set_turn(const int num, boost::optional<game_data &> vars, con
 		vars->get_variable("turn_number") = new_turn;
 }
 
-void tod_manager::set_turn_by_wml(const int num, boost::optional<game_data &> vars, const bool increase_limit_if_needed)
+void tod_manager::set_turn_by_wml(const int num, game_data* vars, const bool increase_limit_if_needed)
 {
 	set_turn(num, vars, increase_limit_if_needed);
 	update_server_information();
@@ -455,7 +455,7 @@ int tod_manager::calculate_current_time(
 	return new_current_time;
 }
 
-bool tod_manager::next_turn(boost::optional<game_data&> vars)
+bool tod_manager::next_turn(game_data* vars)
 {
 	set_turn(turn_ + 1, vars, false);
 	has_turn_event_fired_ = false;

src/tod_manager.hpp

@@ -163,16 +163,16 @@ class tod_manager : public savegame::savegame_config
 		void set_number_of_turns_by_wml(int num);
 
 		/** Dynamically change the current turn number. */
-		void set_turn(const int num, boost::optional<game_data&> vars = boost::none, const bool increase_limit_if_needed = true);
+		void set_turn(const int num, game_data* vars = NULL, const bool increase_limit_if_needed = true);
 		/** Dynamically change the current turn number. */
-		void set_turn_by_wml(const int num, boost::optional<game_data&> vars = boost::none, const bool increase_limit_if_needed = true);
+		void set_turn_by_wml(const int num, game_data* vars = NULL, const bool increase_limit_if_needed = true);
 
 		/**
 		 * Function to move to the next turn.
 		 *
 		 * @returns                   True if time has not expired.
 		 */
-		bool next_turn(boost::optional<game_data&> vars);
+		bool next_turn(game_data* vars);
 
 		/**
 		 * Function to check the end of turns.