Finish ember-data v0.13 upgrade

* update README.md
* remove ID's from findMany url parameters
* cleanup tests and prevent them from printing expected error messages
* fix nested many to many resource URL's
* rework adapter and serializer
* jshint corrections
* use ember-dev for testing
Merge pull request #18 from Juvenal1228/issues/18/test-ember-dev

Remaining Issues from ember-data 13 upgrade