Support to handle additional content type audio/mpeg3
Fix seeking in audio files played over http for urls without file extension
Merge pull request #3042 from Millencolin/http-music-seek-fix

Fix seeking in audio files played over http for urls without file extens...
Expose ACTION_FOO, ICON_TYPE_FOO and KEY_CODE_FOO to addons
Merge pull request #3058 from t4-ravenbird/woa-setting-description

wake-on-access ; add settings-description
Merge pull request #1293 from Karlson2k/win32_fixes

Set of small refactoring and fixes
remove check if running from DVD. this is XBOX legacy which isn't used anymore
configure, external ffmpeg: Drop check for libavresample.
configure: Add --enable-libav-compat option.
Add a fake .pc file for libswresample -> libavresample
DllSwResample: Clean up libavresample support that is broken anyway.
Introduce a libav-hacks library to wrap a compatibility layer with libav.

This copies/pastes some code from FFmpeg but at least allows us to support the fork.
DllAvFormat: map av_stream_get_r_frame_rate when available.
Use av_stream_get_r_frame_rate instead of accessing avstream->r_frame_rate when
available.

From avformat.h:
     * Code outside avformat should access this field using:
     * av_stream_get/set_r_frame_rate(stream)
ActiveAE: Replace deprecated CODEC_ID by AV_CODEC_ID.

The former does not build with FFmpeg 2.0 and I somehow missed this reading the code.
Maybe I should remove the compatibility layer with the old names in the internal FFmpeg to prevent this to happen again.
DllAvUtil: Drop libav hacks and move them to libav_hacks.h.
Move libav check for libavfilter being avframe based to libav_hacks.h
Remove avfilter_graph_parse hacks for libav and move it to libav hacks
DVDVideoCodecFFmpeg: Drop usage of LIBAVFILTER_FROM_* and use LIBAVFILTER_AVFRAME_BASED instead.
DllAvFilter.h: Drop checks for libav and factorize some #if / #else. Those are now done in libav hacks.