added not current month class for days shown not of the selected month
added not current month class for days shown not of the selected month

TuxmAL/simple_calendar,TuxmAL/simple_calendar,excid3/simple_calendar,excid3/simple_calendar,sdbeng/simple_calendar,rodrigoargumedo/simple_calendar,timshingyu/simple_calendar,timshingyu/simple_calendar,sdbeng/simple_calendar,sdbeng/simple_calendar,rodrigoargumedo/simple_calendar,timshingyu/simple_calendar,excid3/simple_calendar,rodrigoargumedo/simple_calendar