* src/stream_output/stream_output.c: small sout_cfg_parser() changes.

* src/stream_output/stream_output.c: small sout_cfg_parser() changes.
* modules/stream_out/duplicate.c: small coding style changes.
* modules/stream_out/transcode.c:
  + Forward the aopts{foo=bar,etc..} and vopts={foo=bar,etc...} options to the encoders.
  + Got rid of the ffmpeg encoder specific options.
* modules/codec/ffmpeg/*:
  + Changed the encoder options to normal config options.
  + Parse the options forwarded by transcode.
* include/vlc_codec.h:
  + encoder_t cleanup.
  + include a "sout_cfg_t *" in encoder_t to allow passing options.