For a very long time now there's been a KDateEdit widget cooking up in kdepim. It's in fact a popular one, and I'm aware of around half a dozen (sometimes modified) copies of that widget. One of the most advanced fork is in Skrooge ATM. During the latest KDE Hacking Session in Toulouse, I sat down with the Skrooge maintainer and produced a refactored version of KDateEdit which also cover their needs.

This patch is about introducing this widget in kdeui. It basically comes with three new classes:
 - KDateEdit itself;
 - KDatePickerPopup used by KDateEdit to popup a calendar picker;
 - KDateValidator used by KDateEdit to validate the input, it's made public as some of the fixup behavior can be tuned.

Note that KDateTable already exposed a class named KDateValidator (much less advanced), so I took care of copying the extra method the former KDateValidator was exposing for BC reasons.

I'm aiming for inclusion in 4.6, so a prompt review would be welcome. Thanks in advance. ;-)