Adds in the mute feature.

- The current mute feature works after the loader has completed, but not
  on load.  This is causing certain machines to play high pitched noises
  upon load.

- I've done some housekeeping in this commit as well to eliminate global
  variables within the module.

The `JSMESS.ready` function now passes the `Module` object as an
argument.
Merge pull request #19 from tbranyen/fix-mute

Adds in the mute feature.
Simple fix to not duplicate efforts.

This should improve the loading speed by not fetching the entire
compiled JS source via XHR and injecting into a script tag.  Instead,
save the script URL and let the browser fetch and execute.