Make sceMpeg and sceAtrac basiclly workable for PC 

I use ffmpeg for video decoding and dshow for at3+ audio. And I have tried my best not to break other platforms yet. In fact, the video part which using ffmpeg may also be possible for other platforms.
By the way, I haven't add the header file and lib for ffmpeg and dshow yet.  I'm not sure how to do this and need some helps.