Merge remote-tracking branch 'qatar/master'

Merge remote-tracking branch 'qatar/master'

* qatar/master:
  FATE: fix the asyncts test
  build: Drop gcc-specific warning flag from header compilation rule
  FATE: add a test for the asyncts audio filter.
  matroskadec: return more correct error code on read error.
  buffersrc: check ff_get_audio_buffer() for errors.
  lavfi: check all ff_get_video_buffer() calls for errors.
  lavfi: check all avfilter_ref_buffer() calls for errors.
  vf_select: avoid an unnecessary avfilter_ref_buffer().
  buffersrc: avoid creating unnecessary buffer reference
  lavfi: use avfilter_unref_bufferp() where appropriate.
  vf_fps: add more error checks.
  vf_fps: fix a memleak on malloc failure.
  lavfi: check all ff_start_frame/draw_slice/end_frame calls for errors
  lavfi: add error handling to end_frame().
  lavfi: add error handling to draw_slice().
  lavfi: add error handling to start_frame().

Conflicts:
	Makefile
	ffplay.c
	libavfilter/buffersrc.c
	libavfilter/vf_boxblur.c
	libavfilter/vf_drawtext.c
	libavfilter/vf_fade.c
	libavfilter/vf_frei0r.c
	libavfilter/vf_hflip.c
	libavfilter/vf_overlay.c
	libavfilter/vf_pad.c
	libavfilter/vf_scale.c
	libavfilter/video.c
	libavfilter/vsrc_color.c

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