Add timezone offset

[scrobbleme]

We've created a patch with a new option for adding a timezone offset.

Using this enables the calender to show a different date as the current date than the browsers date.

This is useful when your site works on the local time of the current logged in user and not the local time of the users browser.

[arian]

Sounds cool, I think a test/demo in the Test folder would be nice so we can test it a little.