Remove int/uint conversion warning

functions.cpp

@@ -888,7 +888,7 @@ void draw(player& player1,b_list& bullets,b_list& bombs,e_list& enemies,w_vec& w
 		mvaddch(wall_p.y,wall_p.x,' ');
 	walls_p.clear();
 	
-	for(int i=0;i<walls.size();i++)
+	for(std::size_t i=0;i<walls.size();i++)
 		for(int k=0;k<walls[i].width;k++)
 			for(int j=0;j<walls[i].height;j++){
 				if(walls[i].health[j][k]==1) attron(COLOR_PAIR(2));