BugFix and Features are added

-The enable alarm from scheduler context is fixed.
   The problem was that if an alarm callback tries to enable another
   alarm the whole alarm queue was resorted which corrupts the
   scheduling activity. (Some alarm were serviced twice while anothers
   none at all) Now the alarm enable function checks by a global
   variable if it is in an alarm callback and if it is the case then
   it doesn't request any sort. (after scheduling the queue is sorted
   anyway)
   
-Dashed line effect is added
   This feature is used with division lines because the waveform isn't
   visible very well with continuous division lines.
   (the greyscale effect with PWM like software functionality wasn't
   successful beacuse it was blinking and faster update rate is not
   available because of the limitation of the bus speed ~10kbyte/s)
   
-Monitor alarms can handle the lags
   Until now if an alarm was not serviced at the proper system time
   when it was expired then that alarm was lost (despite of its
   periodicity). Because of the increasing number of functionility
   in the worst case (lot of alarm expires at the same time or
   interrupts etc) some alarm were lost. Now the scheduler checks if
   there are any alarm which was not serviced and executes them.