gst/elements/gstcapsfilter.c: Reimplement using basetransform, fixes buffer_alloc...

gst/elements/gstcapsfilter.c: Reimplement using basetransform, fixes buffer_alloc proxying among other things.

Original commit message from CVS:
2005-08-04  Andy Wingo  <wingo@pobox.com>

* gst/elements/gstcapsfilter.c: Reimplement using basetransform,
fixes buffer_alloc proxying among other things.

* gst/base/gstbasetransform.c:
* gst/base/gstbasetransform.h:
Revert patch to gstbasetransform from 7-28 removing
delay_configure.

* gst/base/gstbasetransform.h (GstBaseTransformClass.get_size):
* gst/base/gstbasetransform.c (gst_base_transform_get_size):
Semantics changed, should return not the size of the output buffer
but the byte size of a buffer with a given caps.

* gst/base/gstbasetransform.c (gst_base_transform_getcaps): Better
debug object.
(gst_base_transform_configure_caps): Don't set out_size here: (in,
out) are not the pad caps until setcaps finishes.
(gst_base_transform_buffer_alloc): Proxy the buffer_alloc for the
not-in-place case as well. Deal with changing from in-place to
not-in-place within calling pad_alloc_buffer. Still a bit
concerned about the overhead here...