Dirty hack to allow generic wxDatePickerCtrl to compile under MSW.

Dirty hack to allow generic wxDatePickerCtrl to compile under MSW.

Don't make wxDateTimePickerCtrl methods pure virtual in its MSW-specific
version as the generic wx{Date,Time}PickerCtrl implementations not using these
methods also inherit from it currently. This is wrong and would need to be
fixed properly later but for now this hack at least allows the generic classes
to compile and, apparently, work under MSW again.

Remove the equally dirty hack used in the generic wxTimePickerCtrl to allow it
to compile which is not needed any more because this one replaces it.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69489 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775