DLLAvCodec: Do not map avcodec_encode_audio anymore since it is deprecated and now unused within xbmc code.
Configure, internal FFmpeg: Enable asf muxer and wmav2 encoder for ripping CDs to wma2.
CDRip: Add definitions for ripping audio CDs to M4A (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, M4A seems interesting for iTunes users (iOS, OSX, etc.) and WMA for windows users.

Also add the files to the vcxproj since they were missing from there.
Allow selecting AAC and WMA audio CD ripping for the GUI.
Fix build failure with MSVC. Thanks to Jenkins tests.
CDRipEncoder: Add FileSeek function for seeking (required by some libavformat muxers).
CDRip EncoderFFmpeg: Provide a seek callback to avio. It is required for muxing mp4.
Configure, internal FFmpeg: Enable ipod muxer for m4a muxing and CD ripping in this format.