So that's really easy!

Code:
function turnPlayer(var angle, var turnspeed){
   if (player.pan%360 >= angle - 180 && player.pan%360 < angle){
      while(player.pan%360 < angle){
         player.pan += time_step * turnspeed;
      }
      player.pan = angle;
   }else{
      while(player.pan%360 > angle){
         player.pan -= time_step * turnspeed;
      }
      player.pan = angle;
   }
}


not tested!


GameStudio Version: A7 Pro v7.86