[Dev] iCalendar UIDs

[Andi Vajda]

> Trial balloon:  I'm wondering how crucial it is that we use case
> insensitive UUIDs in the repository.

The UUIDs used by the repository try to conform to
http://hegel.ittc.ku.edu/topics/internet/internet-drafts/draft-l/draft-leach-uuids-guids-01.txt
They are a 128 bit number that can be represented as a string in several ways:
  - the standard 36 character long way, using case insensitive hex chars
  - a more compact one I added using base64, 22 characters long, case sensitive

The repository doesn't use case insensitive UUIDs, it uses 128 bit numbers 
generated as UUIDs.

Andi..