[Dev] iCalendar UIDs

[Jeffrey Harris]

Hi Folks,

OK, Andi has convinced me thoroughly that we really don't want to move
away from fast and guaranteed unique UUIDs (and he pointed out the fact
that UUIDs are 128 bit ints, so their case insensitivity when printed as
hexadecimal is an irrelevant implementation detail, oops).

So, I think we should add a unicode UID attribute to Events and Tasks.
Any concerns?

Sincerely,
Jeffrey