Add alarm event support

Closes #580 (closed)

Since the API for alram event is almost the same, that for change event, I did basically copy-paste of chamge event code. The only difference - alarm event without any data can be called only for "state" attribute

Also added is_auto_alarm_on_change_event and set_auto_alarm_on_change_event methods to pyutil.py, related to the alarm events settings