CMOS alarms

[fwsGonzo]

Will help scheduling work that happens over longer periods of time (days, weeks, once a month)
Will help reduce the error (not drift, as that is already fixed) of RTC timestamp function.

[mikeweyandt]

I'm going to look into how to do this, as well as issue #653.

Assuming no one else has made a lot of progress on it, took a look in dev and didn't see any major work done on it within the month.

[mikeweyandt]

How do we feel about:

1. Extending cmos::Time to also handle the alarm methods, like the rtc_time in the linux kernel does
   or
2. Creating cmos::Alarm to handle alarm related methods, it'd be similar code to cmos::Time but might make it easier to read/understand and use.

[alfreb]

Hi @mikeweyandt, this would be great - right now I'd say that anything is better than nothing so feel free :-)