mpegvideo: directly use frames in ff_draw_horiz_band()
h264: directly use frames in ff_h264_draw_horiz_band()
er: move relevant fields from Picture to ERPicture

This is done to disentangle ER from mpegvideo. In order to use a
classic Picture, callers can use ff_mpeg_set_erpic() or use a custom function
to set the fields. Please note that buffers need to be allocated before
calling ff_er_frame_end().
Merge commit '75af13a'

* commit '75af13a':
  mpegvideo: directly use frames in ff_draw_horiz_band()

Conflicts:
	libavcodec/mpegvideo.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '1c79b1625d4d257bfd01eccb84cc0ab355fb9a9e'

* commit '1c79b1625d4d257bfd01eccb84cc0ab355fb9a9e':
  h264: directly use frames in ff_h264_draw_horiz_band()

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'd66e305bd1b4f3e91ae4e7e549148509d0811672'

* commit 'd66e305bd1b4f3e91ae4e7e549148509d0811672':
  er: move relevant fields from Picture to ERPicture

Conflicts:
	libavcodec/error_resilience.c
	libavcodec/h264.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpegvideo: ff_mpeg_set_erpic() clear destination

Fixes crash

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/error_resilience: fix the case when MVs are not available

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>