ext/xvid/: xvid plugin to support more capabilities of XviD codec.

ext/xvid/: xvid plugin to support more capabilities of XviD codec.

Original commit message from CVS:
Patch by: Mark Nauwelaerts <manauw at skynet dot be>
* ext/xvid/gstxvid.c: (gst_xvid_init), (gst_xvid_structure_to_csp),
(gst_xvid_csp_to_caps), (gst_xvid_image_get_size),
(gst_xvid_image_fill):
* ext/xvid/gstxvid.h:
* ext/xvid/gstxviddec.c: (gst_xviddec_class_init),
(gst_xviddec_init), (gst_xviddec_reset), (gst_xviddec_unset),
(gst_xviddec_handle_sink_event), (gst_xviddec_setup),
(gst_xviddec_add_par), (gst_xviddec_negotiate),
(gst_xviddec_decode), (gst_xviddec_chain),
(gst_xviddec_flush_buffers), (gst_xviddec_src_getcaps),
(gst_xviddec_src_link), (gst_xviddec_setcaps),
(gst_xviddec_change_state):
* ext/xvid/gstxviddec.h:
* ext/xvid/gstxvidenc.c: (gst_xvidenc_profile_get_type),
(gst_xvidenc_quant_type_get_type), (gst_xvidenc_pass_get_type),
(gst_xvidenc_get_type), (gst_xvidenc_base_init),
(gst_xvidenc_class_init), (gst_xvidenc_init),
(gst_xvidenc_finalize), (gst_xvidenc_handle_sink_event),
(gst_xvidenc_setup), (gst_xvidenc_setcaps), (gst_xvidenc_encode),
(gst_xvidenc_chain), (gst_xvidenc_flush_buffers),
(gst_xvidenc_set_property), (gst_xvidenc_get_property),
(gst_xvidenc_change_state):
* ext/xvid/gstxvidenc.h:
xvid plugin to support more capabilities of XviD codec.
Fixes #339462.
Some more cleanups here and there.