Pagespeed config and error handling.

Okay, here's what I'm doing here:

1. Changing pagespeed configs to json  by default:
    * pagespeed.js from before still works as it did for backwards compatibility.
    * allowing for 'locale' and 'type' setting in configs.
2. Adding a pagespeed util lib to handle storing error status of pagespeed for better user display.
3. Displaying more detailed error to user.
4. Adding some basic unit tests.

Thoughts?