Features:

* Gtk2::Ex::Dialogs::ChoosePreviewFile
    - use nautilus thumbnailing system
    - add: ask_to_{open,save}_image()
    - add: ask_to_{open,save}_text()
    - ability to add arbitrary filters


Modules:

* Gtk2::Ex::Dialogs::PickDate
* Gtk2::Ex::Dialogs::PickTime
