Merge remote-tracking branch 'qatar/master'

* qatar/master:
  avconv: extend -r to work on any input stream.
  doc/avconv: expand documentation for the -s option.
  avconv: don't print filters inserted by avconv in stream mappings.
  avconv: merge configuration code for complex and simple filters
  avconv: split configuring input filters out of configure_complex_filter

Conflicts:
	configure
	doc/ffmpeg.texi
	ffmpeg.c
	tests/ref/fate/idroq-video-encode

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