* src/input/input_ext-dec.c, include/input_ext-dec.h, modules/codec/araw.c:
   renamed input_NextPES into input_ExtractPES and factorised its code.
* modules/codec/ffmpeg/ffmpeg.c, modules/codec/faad/decoder.c,
   modules/codec/cinepak/cinepak.c: make use of NextPES and GetPES from
   src/input/input_ext-dec.c.
* modules/codec/a52.c: fixed uninitialized variable.