* A calendar popup, based on the new Plasma::Dialog.

I'm using a simple calendar right now. I was planning to use KDatePicker for that, but KDatePicker crashes when setting a stylesheet. So keep it simple for now, and try to find out how to fix KDatePicker->setStylesheet()

* Also, fix saving showTimezone and add an option to easily switch back to the local timezone.
* Clean up some remains from the SVG themable thing

Last, if someone knows a way to prevent the widget from getting a shadow, feel free to tell me. The transparent borders don't look so sexy with shadows, and it kind of conflicts with the visual appearance of the panel.