Upgrade to V2 addon and fix bugs + add enhancements

[x-m-el]

An example test-app using rawDataTable. Uses basics sorting, filtering and pagination.

includes bug fixes and extra features mentioned in the docs, but that were not implemented fully yet.

Rewrites/fixes old tests to the new ember-data-table.

Converts the app the a V2 addon:

1. npm install in the root
2. npm run build in /addon (or npm start, see the scripts in package.json)
3. npm start in /test-app to run the dummy app and tests (so just like before).