gst/audiotestsrc/gstaudiotestsrc.*: update to basesrc changes, implement segmented seeking and eos handling, add a 's...

Original commit message from CVS:
* gst/audiotestsrc/gstaudiotestsrc.c:
(gst_audiostestsrc_wave_get_type), (gst_audio_test_src_class_init),
(gst_audio_test_src_init), (gst_audio_test_src_src_fixate),
(gst_audio_test_src_query), (gst_audio_test_src_create_sine),
(gst_audio_test_src_create_square),
(gst_audio_test_src_create_saw),
(gst_audio_test_src_create_triangle),
(gst_audio_test_src_create_silence),
(gst_audio_test_src_create_white_noise),
(gst_audio_test_src_create_pink_noise),
(gst_audio_test_src_init_sine_table),
(gst_audio_test_src_create_sine_table),
(gst_audio_test_src_change_wave),
(gst_audio_test_src_change_volume), (gst_audio_test_src_do_seek),
(gst_audio_test_src_create), (gst_audio_test_src_set_property):
* gst/audiotestsrc/gstaudiotestsrc.h:
update to basesrc changes, implement segmented seeking and eos handling,
add a 'sine-tab' waveform for performance critical playback