DllAvCodec: map avcodec_encode_audio2
DllAvCodec: map avcodec_fill_audio_frame
DllAvCodec: map avcodec_free_frame.

This makes xbmc require FFmpeg 1.0
AEEncoderFFmpeg: switch to avcodec_encode_audio2 and convert input audio to a format accepted by the encoder if AE does not handle it. Fixes transcoding to AC3 for passthrough (e.g. HDMI).

Without this, with ffmpeg 1.1 and later, xbmc segfaults when trying to transcode
to AC3.

It would be better to have AE to support planar formats but this fallback will be useful in case there are even other audio formats introduced in FFmpeg and is simpler for now.
Merge pull request #2657 from aballier/aacoutput

Fix AAC/AC3 recoding output over SPDIF / HDMI with ffmpeg-1.1 and later (eg, every platform that uses internal ffmpeg)