ember-cli addon

I am publishing the PR so there could be more eyes on it. It is not ready to merge.

- [ ] cleanup generated files
- [ ] complete the README with new instructions
- [ ] make sure I did not make some stuff worse in the process of refactoring :)
- [ ] add some basic tests

Mainly I would like some feedback on how I manage configuration. Is it too much magic?
unrelated to this PR, but people should really just use `init` and `super`