This is an elevator class that represent elevator functionality.
//demo request to api
/api.php?param=open_door - open door
/api.php?param=close_door - close door
/api.php?param=alarm - alarm :)
/api.php?param=request&level=1&direction=up - request elevator on 1 floor with direction up
/api.php?param=send&level=5&direction=up - send elevator to the 5 floor with direction up