CDRip EncoderFFmpeg: Modernize.

Convert to use avformat_alloc_output_context2 and avcodec_encode_audio2.
Convert input audio to the format requested by the encoder if needed.
CDRip FFmpeg: Reduce a bit the avio buffer size as suggsted by libavformat documentation.
CDRip FFmpeg: Write directly to the disc in the avio callback since avio does the buffering for us we do not need to do it twice.
CDRip FFmpeg: Rename MuxerReadPacket to avio_write_callback which reflects more its purpose.
DLLAvCodec: Do not map avcodec_encode_audio anymore since it is deprecated and now unused withing xbmc code.
Confiure, internal FFmpeg: Enable asf muxer and wmav2 encoder for ripping CDs to wma2.
CDRip: Add definitions for ripping audio CDs to AAC and WMA with FFmpeg.

More formats can easily be added but I think we should be parcimonious: If we add too much of them the users will likely be lost.

So far, AAC seems interesting for iTunes users (iOS, OSX, etc.) and WMA for windows users.
Allow selecting AAC and WMA audio CD ripping for the GUI.

This commit should likely be ammended with translation support added.