I did a massive code cleanup. The system seems to works very well and it's extremely stable (no errors or hangups); I will upload it soon. I also added a second webpage for options and a couple of feature:

- intelligent mode: the system automatically preset itself in "perimetral only" or "perimetral and volumetric" mode based on the day time; it can be manually change as usual, of course

- sensor reactivation: you may choose to automatically re-enable or not windows (perimetral) sensors after activating the alarm with open windows