Gthread-2.0 >= 2.6.0 is now required.

* configure.ac.in, src/main.c, src/Makefile.am,
  panel-plugin/screenshooter-plugin.c, panel-plugin/Makefile.am:
  add a dependence on gthread and initialize the threads at startup.
* TODO: updated.
* lib/screenshooter-actions.c: use the URI of the temporary directory
  and not its path, fixes the open with mode.
* lib/screenshooter-dialogs.c:
  - (cb_progress_upload) add the remaining number of bytes to the
    progress bar.
  - (cb_finished_upload) add some debugging information.
  - (save_screenshot_to_local_path) return the save location.
  - (save_screenshot_to_remote_location):
     + tweak the layout of the progress dialog.
     + run the dialog AFTER starting the copy so that it does not block
      everything.
     + delete the temp file after the transfer.
  - (save_screenshot_to) return the save location when saving to a
    local destination.
  - (screenshooter_save_screenshot):
     + destroy the dialog as early as possible so that it does not
       block the main loop.
     + fix the open with mode here too.
* autogen.sh: use git svn instead of git svn.


(Old svn revision: 6901)