Removed the example code from index.js that builds the PEG.js parser in the browser. The parser should now be built on the server.

Since is what a user should do in production anyway, having code that builds the parser in the browser was unnecessary and confusing. This does add an additional build dependency of PEG.js.
The minified script should include the parser in the same file, i.e., libjass.js and ass.pegjs.js should be minifed together into libjass.min.js. The instructions for minification have been updated to reflect this.
Tests have been updated likewise, and now have prettier output.