Added a basic grunt build system.  Generates two

output files in the `build/` directory, one minifies and the other
basically just concatenates.
With this change, `WX.init` is required to be called

in user code to initialize WAAX.  The benefit, it can be used
on a system that doesn't support Web Audio with a graceful failure.
Since the error is thrown from `WX.init`, it can be caught and the
fallback or error can be handled by the user.
Woops.  Only print initialized message once.
Merge branch 'build_system' into dev