Import calendar

@anthonywebb, this pull request is for two changes:
- add logic for the rain delay. I kept it very simple. I did not remove the interrupt, but I do think it is kind of useless.
- fix the UDP 'EBADF' error in a way that should not cause any compatibility issue with the BBB. I suspect the asynchronous mode (callback) is OK too, but you will have to check.(I verified that the UDP broadcast works using WireShark.)