Generate multiple source formats

[eliasku]

Original audiosprite tool generate all formats as source.

"resources": [
    "mygameaudio.caf",
    "mygameaudio.ac3",
    "mygameaudio.mp3",
    "mygameaudio.m4a",
    "mygameaudio.ogg"
  ],

waudsprite select last format and specifies it as src.
For better cross-browser support we need specify all generated sources with priority.
For example, I like to use ogg as primary, but fallback to others if not supported.
What do you think?