Time zones

[quant]

I'm going abroad for some time, and during that time, I will change my laptop time to the relevant time zone. I realize, that in doing so some of my appointments will be wrong.

Maybe we could add time zone attribute to an appointment:

- if an appointment doesn't have "time zone" attribute, the times would be absolute
- if an appointment has "time zone" attribute, the times would be relative, and computed by UR as a difference between "time zone" attribute and currently set Windows time zone.

Thanks