Improve Ember.hasMany

* make it non-embedded by default
* allow to pass options (options['key'] specifies key for the
  association)
* use references instead of ids in HasManyArray, this allows adding
  records without an id to HasManyArray
* properly update relationship if HasManyArray was already created and
  data has been updated
* implement getHasMany function which is called when hasMany association
  is fetched
Implement basic version of belongsTo
Fix FixtureAdapter to properly fetch data in findMany
Save relationship names
Serialize relationships in toJSON
Always create a reference for the record
Ensure that embedded hasMany relationship can get new records
Remove console.log
Fix failing reload test
Merge branch 'relationships-improvements'
Fix license, lol
Add build link
Update README.md
Update build process to grunt
Merge pull request #89 from trek/grunt

Update build process to grunt
Update README.md
Use grunt copy task instead of grunt.file.copy
Merge pull request #104 from trek/grunt

Use grunt copy task instead of grunt.file.copy
release 0.0.2
Fix embedded hasMany relationship with pushObject

The test ensuring that embedded relationship can get new objects had a
syntax mistake, which resulted in assertions not being run. This commit
changes EmbeddedHasManyArray to use references in a similar way
HasManyArray uses them, which allows to unify their behavior when adding
new records to an association.