Fixing tests for Ember Data 1.0.0-beta.5

This PR has a bunch of changes required to work with the new architecture used since ED entered beta.

- [x] Fix `find()` tests
- [x] Fix `findMany()` tests (this one is tough)
- [x] Fix `findQuery()` tests
- [x] Fix `findAll()` tests
- [x] Fix `createRecord()` tests
- [x] Fix `updateRecord()` tests
- [x] Fix `deleteRecords()` tests
- [x] Fix `bulkCommits()` tests (not sure this one is needed anymore)
- [x] Fix `load has many` tests
- [x] Fix `load belongs to` tests
- [x] Fix `save relationship` tests
- [ ] ~~Refactor crazy helpers~~
- [x] Remove memoized variables that prevent data from being truly stored (closes #23)