Use ffmpeg for decoding Atrac3+ in sceAtrac. Thanks Maxim.
Things seem more stable after initializing the AVPacket.

More testing needed though.
Use ffmpeg for Atrac3+ decoding during video playback as well.
Rip out the support for the Atrac3+ plugin. It is gone, to never return.
Windows build fixes
One more buildfix
Define __STDC_CONSTANT_MACROS in CMakeLists.txt so Linux x86 will build.
Clean up SimpleAT3Dec, don't allocate new Frame objects all the time
Update to ffmpeg with Maxim's latest patch
Update FFMPEG submodule with Linux x86 libs based on Maxim's latest patch.
Update submodules
Merge pull request #4221 from hrydgard/maxim-at3plus

Use FFMPEG to decode Atrac3+ audio, thanks to Maxim's new decoder patch.