ext/theora/theoradec.c (theora_dec_src_getcaps): Implement a getcaps to do explicit caps. Needs to be done in all dec...

Original commit message from CVS:
2005-07-01  Andy Wingo  <wingo@pobox.com>

* ext/theora/theoradec.c (theora_dec_src_getcaps): Implement a
getcaps to do explicit caps. Needs to be done in all decoders,
possibly via a base class.

* configure.ac (GST_PLUGIN_LDFLAGS): Add videoscale.

* ext/ogg/gstoggdemux.c (gst_ogg_pad_typefind): No need to set
caps on the sink pad, just rely on the pad template. Also, setting
ANY caps on a pad is not valid because the caps are not fixed.

* sys/ximage/ximagesink.c (gst_ximagesink_buffer_alloc): Set the
caps on the buffer, and get the width from the desired_caps if
they're set.
(gst_ximagesink_renegotiate_size): Implement via setting the
desired_caps on the ximagesink.
(gst_ximagesink_setcaps): Only reset the width of the player if it
wasn't already set. Not sure if this is right.
(gst_ximagesink_show_frame): Memcpy only for normal buffers.

* sys/ximage/ximagesink.h (desired_caps): New field, is the caps
that the user wants. NULL unless the window has been resized.

* gst/volume/gstvolume.c (volume_transform): Adapt to
basetransform refcount changes.