Added preliminar support for embedded records:

- Only works for loading record (it is the only functionality provided by ember-data currently)
- Currently, in the property mapping both embedded=load and custom key properties must be added:

  Adapter.map('Task', {
    owner: {embedded: 'load', key: 'owner'}
  });
Extending embedded methods
Updated to ember-data revision 11
Fix typo in Readme
createRecord success call didCreateRecord
Simplified sideloading
Tastypie default does not implement sideload feature