removed compiler warning in player_item_manager.cpp

src/gameplay/item/player_item_manager.cpp

@@ -121,7 +121,7 @@ namespace gdw {
 	void player_item_manager::update(float dt) {
 		std::vector<accelerator_type*> accel_del_queue;
 
-		for(int i = 0; i < accelerators_.size(); i++) {
+		for(auto i = 0u; i < accelerators_.size(); i++) {
 			auto a = accelerators_[i];
 			auto ent = engine_.entity_manager().resolve(a->main);
 			auto &game_input_manager = engine_.game_play_system().game_input_manager();
@@ -146,7 +146,7 @@ namespace gdw {
 
 		// emp management
 		std::vector<emp_type*> emp_del_queue;
-		for(int i = 0; i < emps_.size(); i++) {
+		for(auto i = 0u; i < emps_.size(); i++) {
 			auto e = emps_[i];
 
 			e->alive_timer += dt;