Time zone settings added to Mac OS X version

[dirkpitt]

I added timezone settings to the OS X version's Set Time panel. This is basically the same functionality that was recently added to the Windows version.

There are two extra popup selections:
- Time Zone:

1. Local Time (your system's time zone) <-Same as current behaviour
2. UTC (GMT)

- Format:

1. Default (date/time format determined in some arbitrary fashion by your system's International settings),
2. Time zone name suffixed <-Same as current behaviour
3. UTC offset (+nnnn)

Selecting an option takes effect immediately.
To try them out, get the latest source from CVS.