Add 'move to top' and 'move to bottom' buttons

These do exactly what they say on the tin.

Signed-off-by: Andrew Clayton <andrew@digital-domain.net>
Fix a couple of memory leaks

In cb_move_up() and cb_move_down() the path acquired by
gtk_tree_model_get_path() needs to be free'd.

Signed-off-by: Andrew Clayton <andrew@digital-domain.net>
Add multiple selection support

Allow the move & delete operations to work on multiple rows.

Signed-off-by: Andrew Clayton <andrew@digital-domain.net>
Move the 'move to bottom' button below the 'move down' button

So we now have

    Move to Top
    Move Up
    Move Down
    Move to Bottom

    Delete

this seems slightly more logical.

Signed-off-by: Andrew Clayton <andrew@digital-domain.net>
Add a description of the program in the about window

Signed-off-by: Andrew Clayton <andrew@digital-domain.net>
reordinator 002

Signed-off-by: Andrew Clayton <andrew@digital-domain.net>