Merge remote-tracking branch 'qatar/master'

Merge remote-tracking branch 'qatar/master'

* qatar/master:
  Add a tool that uses avio to read and write, doing a plain copy of data
  ARM: fix build with FFT enabled and MDCT disabled
  lavf: force single-threaded decoding in avformat_find_stream_info
  avidec: migrate last of lavf from FF_ER_* to AV_EF_*
  avserver: fix build after the next bump.

Conflicts:
	libavformat/Makefile
	libavformat/avidec.c
	libavformat/utils.c

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