* lib/screenshooter-utils.{c,h}: add a close item to the
  ScreenshotData structure. Allows the user to choose between
  closing the application and taking another screenshot.
* src/main.c (cb_dialog_response): implement the close stuff.
* lib/screenshooter-dialogs.c: Rewrite most of the interface.
  - use tables to align the widgets.
  - use a two column layout.
  - add an option to close/ don't close the application after
    taking a screenshot.



(Old svn revision: 7006)