elpaso/Rtc_Pcf8563 — pull request #10 by cevich (2014-12-02 23:23:31+00:00)
Title: Add a handful of date-related utility methods

These came from a formerly tested source, however I haven't re-tested they're all correct after integrating here. I'll take care of that later, unless somebody else gets to it first :wink:

* isLeapYear()
* daysInMonth()
* daysInYear()
* whatWeekday()

I made them all pure so they can be used with stored values. For
example, calculating durations across month/year boundariess in
arbitrary terms (i.e. days, minutes, seconds, etc). This also
helps provide enough information to fill out the standard time_t
structure.

Signed-off-by: Chris Evich