First step towards adding "copy to clipboard" functionnality. This commits may break a few things which will be fixed later. Based on the work of David Collins.

  * lib/screenshooter-utils.{c,h}:
    - fix includes
    - cleanup prototypes
    - (screenshooter_copy_to_clipboard) Partially apply a patch by 
      David Collins to add copying to clipboard possibility.
    - add post screenshot actions in the ScreenshotData struct, in
      (screenshooter_read_rc_file) and in (screenshooter_write_rc_file)
      (Patch by David Collins).
    - remove all references to "none" application.
  * lib/screenshooter-dialogs.{c,h}:
    - remove all references to none application.
    - remove (cb_combo_active_item_set_sensitive).
    - remove "none" item from (add_item).
  * lib/screenshooter-actions.{c,h}:
    - added to manage post screenshot actions.
  * lib/Mafile.am: add new source files.
  * lib/libscreenshooter.h: include screenshooter-actions.h.
  * src/main.c, panel-plugin/screenshooter-plugin.c: 
    - use (screenshooter_take_and_output_screenshot).


(Old svn revision: 6156)