Support mp3 and h264 in video and audio tag

Node-Webkit don't support mp3 and h264 in video and audio tag by default because of patented media formats.
But here's how to add support.

Important The codec libs you are going to need to work properly are hosted here
ps: (windows is the .dll) and (Mac is the .so)

Please follow this instructions on Node-Webkit wiki on how to install.
Just don't forget to use the codec libs hosted here