Add note about conditional requests to README.md
Incorporate some ideas from jquery boilerplate

* Plugin object is now a named object (GUAWPlugin) and created via the new keyword
* The instance of the plugin is now saved with the DOM element, which protects against multiple instantiations on a single DOM element
* Some functions have been moved to the object prototype
Update version to 0.2.0
Update dist code for v0.2.0