ffplay: use format title metadata to set window caption.
examples/filtering_audio: enable ref counted frames

Fixes accessing freed memory

Signe-off-by: Michael Niedermayer <michaelni@gmx.at>
examples/filtering_audio: get rid of AVABufferSinkParams

AVABufferSinkParams are ignored by avfilter_graph_create_filter,
therefore the example is misleading.  Use av_opt_set_int_list to
configure abuffersink directly.

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