libs/gst/base/gstbasetransform.c (gst_base_transform_activate): Factor start/stop into this private function instead ...

Original commit message from CVS:
2007-01-12  Andy Wingo  <wingo@pobox.com>

* libs/gst/base/gstbasetransform.c (gst_base_transform_activate):
Factor start/stop into this private function instead of partially
in activate functions and partially in the change_state function.
Fixes setup before the element has changed from READY->PAUSED, as
is the case in pull-mode pipelines.
(gst_base_transform_sink_activate_push)
(gst_base_transform_src_activate_pull): Refactor to use
gst_base_transform_activate().
(gst_base_transform_change_state): Removed, not needed any more.

* libs/gst/base/gstbasesink.c (gst_base_sink_negotiate_pull):
Truncate before fixating.