check/pipelines/simple_launch_lines.c: Small update, use API as stated in design...

check/pipelines/simple_launch_lines.c: Small update, use API as stated in design docs.

Original commit message from CVS:
* check/pipelines/simple_launch_lines.c: (run_pipeline):
Small update, use API as stated in design docs.

* examples/seeking/seek.c: (make_avi_msmpeg4v3_mp3_pipeline),
(update_scale), (do_seek), (seek_cb), (set_update_scale),
(start_seek), (stop_seek), (play_cb), (pause_cb), (stop_cb),
(message_received), (main):
Updated seek example for GOption. Some usability improvements.