ext/swfdec/gstswfdec.*: Fix negotiation.

ext/swfdec/gstswfdec.*: Fix negotiation.

Original commit message from CVS:
* ext/swfdec/gstswfdec.c: (gst_swfdec_video_getcaps),
(gst_swfdec_video_link), (copy_image), (gst_swfdec_loop),
(gst_swfdec_init), (gst_swfdec_change_state):
* ext/swfdec/gstswfdec.h:
Fix negotiation.
* gst/adder/gstadder.c: (gst_adder_link), (gst_adder_init),
(gst_adder_request_new_pad): Fix negotiation.
* gst/goom/gstgoom.c: (gst_goom_init), (gst_goom_src_fixate):
Add a fixate function.
* gst/intfloat/gstfloat2int.c:
* gst/intfloat/gstfloat2int.h:
* gst/intfloat/gstint2float.c:
* gst/intfloat/gstint2float.h:
Completely rewrite the negotiation.  Doesn't quite work yet,
due to some buffer-frames problem.