Get Torii ready for use as an ember-addon

 * add ember-addon/index.js to provide include hooks
 * remove unused s3.js task options
 * update package.json to include 'ember-addon' keyword
 * update package.json to look good for npm publish
 * remove ember-shim and qunit-shim in vendor
 * clean up some unused directories in test/
 * update npmignore