ffplay: reorder the filters to ensure that inputs of the custom filters are merged first

For more info see http://ffmpeg.org/pipermail/ffmpeg-user/2013-December/018761.html

Signed-off-by: Marton Balint <cus@passwd.hu>
ffplay: flush subtitle codecs as well with null packets

Signed-off-by: Marton Balint <cus@passwd.hu>
Merge remote-tracking branch 'cus/stable'

* cus/stable:
  ffplay: flush subtitle codecs as well with null packets
  ffplay: reorder the filters to ensure that inputs of the custom filters are merged first

Merged-by: Michael Niedermayer <michaelni@gmx.at>
configure: use real libfdk-aac version instead of API version in help text

Also use real name with a '-' instead of '_'.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>