Original commit message from CVS:
* gst/base/gstbasetransform.c: (gst_base_transform_setcaps):
Added more debug info in the negotiate process.

* gst/gstmessage.h:
Prepare for segment playback.

* gst/gstpad.c: (gst_pad_accept_caps), (gst_pad_set_caps):
Better debugging.

* gst/gstutils.c:
Some more docs.

* tools/gst-launch.c: (main):
NULL pipeline on errors.