Remove old probes, add new g-signal-based probes and some utility functions.

Remove old probes, add new g-signal-based probes and some utility functions.

Original commit message from CVS:
* docs/gst/gstreamer-sections.txt:
* docs/gst/tmpl/gstpad.sgml:
* docs/gst/tmpl/gstprobe.sgml:
* gst/Makefile.am:
* gst/gstpad.c: (_gst_do_pass_data_accumulator),
(gst_pad_class_init), (gst_pad_init), (gst_pad_chain),
(gst_pad_push), (gst_pad_get_range), (gst_pad_pull_range),
(gst_pad_push_event), (gst_pad_send_event):
* gst/gstpad.h:
* gst/gstutils.c: (gst_pad_add_data_probe),
(gst_pad_add_event_probe), (gst_pad_add_buffer_probe),
(gst_pad_remove_data_probe), (gst_pad_remove_event_probe),
(gst_pad_remove_buffer_probe):
* gst/gstutils.h:
Remove old probes, add new g-signal-based probes and some utility
functions.