* cigaes/master:
  lavfi/dualinput: fix shortest option.
  lavfi/vf_tile: use av_make_q.
  lavfi/avf_concat: use av_make_q.
  lavfi/af_amerge: use av_make_q.
  lavu/rational: add syntactic sugar.
Merged-by: Michael Niedermayer <michaelni@gmx.at>